Java中的使用及连接Redis数据库的方法
Java中的使用及连接Redis数据库的方法?相信很多没有经验的人对此束手无策,为此本文总结了问题出现的原因和解决方法,通过这篇文章希望你能解决这个问题。
1. 在IDEA中搭建Redis
1.1 创建项目
1.2 添加依赖(不够手动添加)
<dependencies> <!-- 1、 Jedis--> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.9.0</version> </dependency> <!-- 2、 Junit测试--> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.1.2</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies>
1.3 测试环境是否搭建成功
@Test public void test0() { //连接Redis Jedis jedis = new Jedis("127.0.0.1", 6379); //获取kak String kaka = jedis.get("kak"); log.info(kaka); //创建datex String datex = jedis.set("datex", new Date().toString()); //获取datex String datex1 = jedis.get("datex"); log.info(datex1); //关闭资源 jedis.close(); }
1.4 利用json存储数据
@Test public void test1() { JedisPool pool = new JedisPool("127.0.0.1", 6379); Jedis jedis = pool.getResource(); Student student = new Student(1001, "kak", "man", "20"); String key = "student"; String field = "1001"; String s = JsonUtils.objectToJson(student); String value = s; jedis.hset(key, field, value); String hget = jedis.hget(key, field); log.info(hget); jedis.close(); }
1.5 以byte的形式存储对象
@Test public void test02() { //连接redis Jedis jedis = new Jedis("127.0.0.1", 6379); String key = "Student"; Student value = new Student(1002, "taotao", "woman", "20"); //将key和value转换为byte[] byte[] byteKey = SerializationUtils.serialize(key); byte[] byteValue = SerializationUtils.serialize(value); //将key和value存储到redis中 jedis.set(byteKey, byteValue); //获取value值 byte[] bytes = jedis.get(byteKey); //bytes反序列化为Student对象 Student stu = (Student) SerializationUtils.deserialize(bytes); System.out.println(stu); jedis.close(); }
1.6 加入连接池的操作
使用连接池操作,可以避免频繁的创建和销毁连接对象的消耗资源
@Test public void test3(){ //创建连接池 GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig(); poolConfig.setMaxTotal(100);//连接池中的最大活跃数 poolConfig.setMaxIdle(10);//最大空闲数 poolConfig.setMinIdle(5);//最小空闲数 poolConfig.setMaxWaitMillis(3000);//连接池空了,3000毫秒后没有获取Jedis对象,超时 //创建连接池 JedisPool pool = new JedisPool(poolConfig,"127.0.0.1",6379); //通过连接池获取Jedis对象 Jedis resource = pool.getResource(); //获取上面添加的datex String value = resource.get("datex"); log.info(value); resource.close(); }
1.7 管道操作
Redis的管道操作,执行一个命令需要先发送请求到Redis,需要经历网络延迟,Redis还需给客户端一个响应;如果需要一次操作多个命令,可以通过管道,将命令放到客户端的一个Pipeline中,之后一次将命令发送到服务端,服务端一次性返回到客户端;
@Test public void test3(){ //创建连接池 GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig(); poolConfig.setMaxTotal(100);//连接池中的最大活跃数 poolConfig.setMaxIdle(10);//最大空闲数 poolConfig.setMinIdle(5);//最小空闲数 poolConfig.setMaxWaitMillis(3000);//连接池空了,3000毫秒后没有获取Jedis对象,超时 //创建连接池 JedisPool pool = new JedisPool(poolConfig,"127.0.0.1",6379); //通过连接池获取Jedis对象 Jedis resource = pool.getResource(); //获取上面添加的datex String value = resource.get("datex"); log.info(value); resource.close(); }
2. 从数据中查询数据
场景:
将数据存入Redis中,避免访问量过大,造成数据库奔溃;
2.1 生成实体类
@Test public void test3(){ //创建连接池 GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig(); poolConfig.setMaxTotal(100);//连接池中的最大活跃数 poolConfig.setMaxIdle(10);//最大空闲数 poolConfig.setMinIdle(5);//最小空闲数 poolConfig.setMaxWaitMillis(3000);//连接池空了,3000毫秒后没有获取Jedis对象,超时 //创建连接池 JedisPool pool = new JedisPool(poolConfig,"127.0.0.1",6379); //通过连接池获取Jedis对象 Jedis resource = pool.getResource(); //获取上面添加的datex String value = resource.get("datex"); log.info(value); resource.close(); }
2.2 生成实体模板类
package com.sx.kak.po; import java.util.ArrayList; import java.util.List; public class StudentExample { protected String orderByClause; protected boolean distinct; protected List<Criteria> oredCriteria; public StudentExample() { oredCriteria = new ArrayList<Criteria>(); } public void setOrderByClause(String orderByClause) { this.orderByClause = orderByClause; } public String getOrderByClause() { return orderByClause; } public void setDistinct(boolean distinct) { this.distinct = distinct; } public boolean isDistinct() { return distinct; } public List<Criteria> getOredCriteria() { return oredCriteria; } public void or(Criteria criteria) { oredCriteria.add(criteria); } public Criteria or() { Criteria criteria = createCriteriaInternal(); oredCriteria.add(criteria); return criteria; } public Criteria createCriteria() { Criteria criteria = createCriteriaInternal(); if (oredCriteria.size() == 0) { oredCriteria.add(criteria); } return criteria; } protected Criteria createCriteriaInternal() { Criteria criteria = new Criteria(); return criteria; } public void clear() { oredCriteria.clear(); orderByClause = null; distinct = false; } protected abstract static class GeneratedCriteria { protected List<Criterion> criteria; protected GeneratedCriteria() { super(); criteria = new ArrayList<Criterion>(); } public boolean isValid() { return criteria.size() > 0; } public List<Criterion> getAllCriteria() { return criteria; } public List<Criterion> getCriteria() { return criteria; } protected void addCriterion(String condition) { if (condition == null) { throw new RuntimeException("Value for condition cannot be null"); } criteria.add(new Criterion(condition)); } protected void addCriterion(String condition, Object value, String property) { if (value == null) { throw new RuntimeException("Value for " + property + " cannot be null"); } criteria.add(new Criterion(condition, value)); } protected void addCriterion(String condition, Object value1, Object value2, String property) { if (value1 == null || value2 == null) { throw new RuntimeException("Between values for " + property + " cannot be null"); } criteria.add(new Criterion(condition, value1, value2)); } public Criteria andIdIsNull() { addCriterion("id is null"); return (Criteria) this; } public Criteria andIdIsNotNull() { addCriterion("id is not null"); return (Criteria) this; } public Criteria andIdEqualTo(Integer value) { addCriterion("id =", value, "id"); return (Criteria) this; } public Criteria andIdNotEqualTo(Integer value) { addCriterion("id <>", value, "id"); return (Criteria) this; } public Criteria andIdGreaterThan(Integer value) { addCriterion("id >", value, "id"); return (Criteria) this; } public Criteria andIdGreaterThanOrEqualTo(Integer value) { addCriterion("id >=", value, "id"); return (Criteria) this; } public Criteria andIdLessThan(Integer value) { addCriterion("id <", value, "id"); return (Criteria) this; } public Criteria andIdLessThanOrEqualTo(Integer value) { addCriterion("id <=", value, "id"); return (Criteria) this; } public Criteria andIdIn(List<Integer> values) { addCriterion("id in", values, "id"); return (Criteria) this; } public Criteria andIdNotIn(List<Integer> values) { addCriterion("id not in", values, "id"); return (Criteria) this; } public Criteria andIdBetween(Integer value1, Integer value2) { addCriterion("id between", value1, value2, "id"); return (Criteria) this; } public Criteria andIdNotBetween(Integer value1, Integer value2) { addCriterion("id not between", value1, value2, "id"); return (Criteria) this; } public Criteria andNameIsNull() { addCriterion("NAME is null"); return (Criteria) this; } public Criteria andNameIsNotNull() { addCriterion("NAME is not null"); return (Criteria) this; } public Criteria andNameEqualTo(String value) { addCriterion("NAME =", value, "name"); return (Criteria) this; } public Criteria andNameNotEqualTo(String value) { addCriterion("NAME <>", value, "name"); return (Criteria) this; } public Criteria andNameGreaterThan(String value) { addCriterion("NAME >", value, "name"); return (Criteria) this; } public Criteria andNameGreaterThanOrEqualTo(String value) { addCriterion("NAME >=", value, "name"); return (Criteria) this; } public Criteria andNameLessThan(String value) { addCriterion("NAME <", value, "name"); return (Criteria) this; } public Criteria andNameLessThanOrEqualTo(String value) { addCriterion("NAME <=", value, "name"); return (Criteria) this; } public Criteria andNameLike(String value) { addCriterion("NAME like", value, "name"); return (Criteria) this; } public Criteria andNameNotLike(String value) { addCriterion("NAME not like", value, "name"); return (Criteria) this; } public Criteria andNameIn(List<String> values) { addCriterion("NAME in", values, "name"); return (Criteria) this; } public Criteria andNameNotIn(List<String> values) { addCriterion("NAME not in", values, "name"); return (Criteria) this; } public Criteria andNameBetween(String value1, String value2) { addCriterion("NAME between", value1, value2, "name"); return (Criteria) this; } public Criteria andNameNotBetween(String value1, String value2) { addCriterion("NAME not between", value1, value2, "name"); return (Criteria) this; } public Criteria andSexIsNull() { addCriterion("sex is null"); return (Criteria) this; } public Criteria andSexIsNotNull() { addCriterion("sex is not null"); return (Criteria) this; } public Criteria andSexEqualTo(String value) { addCriterion("sex =", value, "sex"); return (Criteria) this; } public Criteria andSexNotEqualTo(String value) { addCriterion("sex <>", value, "sex"); return (Criteria) this; } public Criteria andSexGreaterThan(String value) { addCriterion("sex >", value, "sex"); return (Criteria) this; } public Criteria andSexGreaterThanOrEqualTo(String value) { addCriterion("sex >=", value, "sex"); return (Criteria) this; } public Criteria andSexLessThan(String value) { addCriterion("sex <", value, "sex"); return (Criteria) this; } public Criteria andSexLessThanOrEqualTo(String value) { addCriterion("sex <=", value, "sex"); return (Criteria) this; } public Criteria andSexLike(String value) { addCriterion("sex like", value, "sex"); return (Criteria) this; } public Criteria andSexNotLike(String value) { addCriterion("sex not like", value, "sex"); return (Criteria) this; } public Criteria andSexIn(List<String> values) { addCriterion("sex in", values, "sex"); return (Criteria) this; } public Criteria andSexNotIn(List<String> values) { addCriterion("sex not in", values, "sex"); return (Criteria) this; } public Criteria andSexBetween(String value1, String value2) { addCriterion("sex between", value1, value2, "sex"); return (Criteria) this; } public Criteria andSexNotBetween(String value1, String value2) { addCriterion("sex not between", value1, value2, "sex"); return (Criteria) this; } public Criteria andAgeIsNull() { addCriterion("age is null"); return (Criteria) this; } public Criteria andAgeIsNotNull() { addCriterion("age is not null"); return (Criteria) this; } public Criteria andAgeEqualTo(String value) { addCriterion("age =", value, "age"); return (Criteria) this; } public Criteria andAgeNotEqualTo(String value) { addCriterion("age <>", value, "age"); return (Criteria) this; } public Criteria andAgeGreaterThan(String value) { addCriterion("age >", value, "age"); return (Criteria) this; } public Criteria andAgeGreaterThanOrEqualTo(String value) { addCriterion("age >=", value, "age"); return (Criteria) this; } public Criteria andAgeLessThan(String value) { addCriterion("age <", value, "age"); return (Criteria) this; } public Criteria andAgeLessThanOrEqualTo(String value) { addCriterion("age <=", value, "age"); return (Criteria) this; } public Criteria andAgeLike(String value) { addCriterion("age like", value, "age"); return (Criteria) this; } public Criteria andAgeNotLike(String value) { addCriterion("age not like", value, "age"); return (Criteria) this; } public Criteria andAgeIn(List<String> values) { addCriterion("age in", values, "age"); return (Criteria) this; } public Criteria andAgeNotIn(List<String> values) { addCriterion("age not in", values, "age"); return (Criteria) this; } public Criteria andAgeBetween(String value1, String value2) { addCriterion("age between", value1, value2, "age"); return (Criteria) this; } public Criteria andAgeNotBetween(String value1, String value2) { addCriterion("age not between", value1, value2, "age"); return (Criteria) this; } } public static class Criteria extends GeneratedCriteria { protected Criteria() { super(); } } public static class Criterion { private String condition; private Object value; private Object secondValue; private boolean noValue; private boolean singleValue; private boolean betweenValue; private boolean listValue; private String typeHandler; public String getCondition() { return condition; } public Object getValue() { return value; } public Object getSecondValue() { return secondValue; } public boolean isNoValue() { return noValue; } public boolean isSingleValue() { return singleValue; } public boolean isBetweenValue() { return betweenValue; } public boolean isListValue() { return listValue; } public String getTypeHandler() { return typeHandler; } protected Criterion(String condition) { super(); this.condition = condition; this.typeHandler = null; this.noValue = true; } protected Criterion(String condition, Object value, String typeHandler) { super(); this.condition = condition; this.value = value; this.typeHandler = typeHandler; if (value instanceof List<?>) { this.listValue = true; } else { this.singleValue = true; } } protected Criterion(String condition, Object value) { this(condition, value, null); } protected Criterion(String condition, Object value, Object secondValue, String typeHandler) { super(); this.condition = condition; this.value = value; this.secondValue = secondValue; this.typeHandler = typeHandler; this.betweenValue = true; } protected Criterion(String condition, Object value, Object secondValue) { this(condition, value, secondValue, null); } } }
2.3 生成studentMapper.java
package com.sx.kak.po; import java.util.ArrayList; import java.util.List; public class StudentExample { protected String orderByClause; protected boolean distinct; protected List<Criteria> oredCriteria; public StudentExample() { oredCriteria = new ArrayList<Criteria>(); } public void setOrderByClause(String orderByClause) { this.orderByClause = orderByClause; } public String getOrderByClause() { return orderByClause; } public void setDistinct(boolean distinct) { this.distinct = distinct; } public boolean isDistinct() { return distinct; } public List<Criteria> getOredCriteria() { return oredCriteria; } public void or(Criteria criteria) { oredCriteria.add(criteria); } public Criteria or() { Criteria criteria = createCriteriaInternal(); oredCriteria.add(criteria); return criteria; } public Criteria createCriteria() { Criteria criteria = createCriteriaInternal(); if (oredCriteria.size() == 0) { oredCriteria.add(criteria); } return criteria; } protected Criteria createCriteriaInternal() { Criteria criteria = new Criteria(); return criteria; } public void clear() { oredCriteria.clear(); orderByClause = null; distinct = false; } protected abstract static class GeneratedCriteria { protected List<Criterion> criteria; protected GeneratedCriteria() { super(); criteria = new ArrayList<Criterion>(); } public boolean isValid() { return criteria.size() > 0; } public List<Criterion> getAllCriteria() { return criteria; } public List<Criterion> getCriteria() { return criteria; } protected void addCriterion(String condition) { if (condition == null) { throw new RuntimeException("Value for condition cannot be null"); } criteria.add(new Criterion(condition)); } protected void addCriterion(String condition, Object value, String property) { if (value == null) { throw new RuntimeException("Value for " + property + " cannot be null"); } criteria.add(new Criterion(condition, value)); } protected void addCriterion(String condition, Object value1, Object value2, String property) { if (value1 == null || value2 == null) { throw new RuntimeException("Between values for " + property + " cannot be null"); } criteria.add(new Criterion(condition, value1, value2)); } public Criteria andIdIsNull() { addCriterion("id is null"); return (Criteria) this; } public Criteria andIdIsNotNull() { addCriterion("id is not null"); return (Criteria) this; } public Criteria andIdEqualTo(Integer value) { addCriterion("id =", value, "id"); return (Criteria) this; } public Criteria andIdNotEqualTo(Integer value) { addCriterion("id <>", value, "id"); return (Criteria) this; } public Criteria andIdGreaterThan(Integer value) { addCriterion("id >", value, "id"); return (Criteria) this; } public Criteria andIdGreaterThanOrEqualTo(Integer value) { addCriterion("id >=", value, "id"); return (Criteria) this; } public Criteria andIdLessThan(Integer value) { addCriterion("id <", value, "id"); return (Criteria) this; } public Criteria andIdLessThanOrEqualTo(Integer value) { addCriterion("id <=", value, "id"); return (Criteria) this; } public Criteria andIdIn(List<Integer> values) { addCriterion("id in", values, "id"); return (Criteria) this; } public Criteria andIdNotIn(List<Integer> values) { addCriterion("id not in", values, "id"); return (Criteria) this; } public Criteria andIdBetween(Integer value1, Integer value2) { addCriterion("id between", value1, value2, "id"); return (Criteria) this; } public Criteria andIdNotBetween(Integer value1, Integer value2) { addCriterion("id not between", value1, value2, "id"); return (Criteria) this; } public Criteria andNameIsNull() { addCriterion("NAME is null"); return (Criteria) this; } public Criteria andNameIsNotNull() { addCriterion("NAME is not null"); return (Criteria) this; } public Criteria andNameEqualTo(String value) { addCriterion("NAME =", value, "name"); return (Criteria) this; } public Criteria andNameNotEqualTo(String value) { addCriterion("NAME <>", value, "name"); return (Criteria) this; } public Criteria andNameGreaterThan(String value) { addCriterion("NAME >", value, "name"); return (Criteria) this; } public Criteria andNameGreaterThanOrEqualTo(String value) { addCriterion("NAME >=", value, "name"); return (Criteria) this; } public Criteria andNameLessThan(String value) { addCriterion("NAME <", value, "name"); return (Criteria) this; } public Criteria andNameLessThanOrEqualTo(String value) { addCriterion("NAME <=", value, "name"); return (Criteria) this; } public Criteria andNameLike(String value) { addCriterion("NAME like", value, "name"); return (Criteria) this; } public Criteria andNameNotLike(String value) { addCriterion("NAME not like", value, "name"); return (Criteria) this; } public Criteria andNameIn(List<String> values) { addCriterion("NAME in", values, "name"); return (Criteria) this; } public Criteria andNameNotIn(List<String> values) { addCriterion("NAME not in", values, "name"); return (Criteria) this; } public Criteria andNameBetween(String value1, String value2) { addCriterion("NAME between", value1, value2, "name"); return (Criteria) this; } public Criteria andNameNotBetween(String value1, String value2) { addCriterion("NAME not between", value1, value2, "name"); return (Criteria) this; } public Criteria andSexIsNull() { addCriterion("sex is null"); return (Criteria) this; } public Criteria andSexIsNotNull() { addCriterion("sex is not null"); return (Criteria) this; } public Criteria andSexEqualTo(String value) { addCriterion("sex =", value, "sex"); return (Criteria) this; } public Criteria andSexNotEqualTo(String value) { addCriterion("sex <>", value, "sex"); return (Criteria) this; } public Criteria andSexGreaterThan(String value) { addCriterion("sex >", value, "sex"); return (Criteria) this; } public Criteria andSexGreaterThanOrEqualTo(String value) { addCriterion("sex >=", value, "sex"); return (Criteria) this; } public Criteria andSexLessThan(String value) { addCriterion("sex <", value, "sex"); return (Criteria) this; } public Criteria andSexLessThanOrEqualTo(String value) { addCriterion("sex <=", value, "sex"); return (Criteria) this; } public Criteria andSexLike(String value) { addCriterion("sex like", value, "sex"); return (Criteria) this; } public Criteria andSexNotLike(String value) { addCriterion("sex not like", value, "sex"); return (Criteria) this; } public Criteria andSexIn(List<String> values) { addCriterion("sex in", values, "sex"); return (Criteria) this; } public Criteria andSexNotIn(List<String> values) { addCriterion("sex not in", values, "sex"); return (Criteria) this; } public Criteria andSexBetween(String value1, String value2) { addCriterion("sex between", value1, value2, "sex"); return (Criteria) this; } public Criteria andSexNotBetween(String value1, String value2) { addCriterion("sex not between", value1, value2, "sex"); return (Criteria) this; } public Criteria andAgeIsNull() { addCriterion("age is null"); return (Criteria) this; } public Criteria andAgeIsNotNull() { addCriterion("age is not null"); return (Criteria) this; } public Criteria andAgeEqualTo(String value) { addCriterion("age =", value, "age"); return (Criteria) this; } public Criteria andAgeNotEqualTo(String value) { addCriterion("age <>", value, "age"); return (Criteria) this; } public Criteria andAgeGreaterThan(String value) { addCriterion("age >", value, "age"); return (Criteria) this; } public Criteria andAgeGreaterThanOrEqualTo(String value) { addCriterion("age >=", value, "age"); return (Criteria) this; } public Criteria andAgeLessThan(String value) { addCriterion("age <", value, "age"); return (Criteria) this; } public Criteria andAgeLessThanOrEqualTo(String value) { addCriterion("age <=", value, "age"); return (Criteria) this; } public Criteria andAgeLike(String value) { addCriterion("age like", value, "age"); return (Criteria) this; } public Criteria andAgeNotLike(String value) { addCriterion("age not like", value, "age"); return (Criteria) this; } public Criteria andAgeIn(List<String> values) { addCriterion("age in", values, "age"); return (Criteria) this; } public Criteria andAgeNotIn(List<String> values) { addCriterion("age not in", values, "age"); return (Criteria) this; } public Criteria andAgeBetween(String value1, String value2) { addCriterion("age between", value1, value2, "age"); return (Criteria) this; } public Criteria andAgeNotBetween(String value1, String value2) { addCriterion("age not between", value1, value2, "age"); return (Criteria) this; } } public static class Criteria extends GeneratedCriteria { protected Criteria() { super(); } } public static class Criterion { private String condition; private Object value; private Object secondValue; private boolean noValue; private boolean singleValue; private boolean betweenValue; private boolean listValue; private String typeHandler; public String getCondition() { return condition; } public Object getValue() { return value; } public Object getSecondValue() { return secondValue; } public boolean isNoValue() { return noValue; } public boolean isSingleValue() { return singleValue; } public boolean isBetweenValue() { return betweenValue; } public boolean isListValue() { return listValue; } public String getTypeHandler() { return typeHandler; } protected Criterion(String condition) { super(); this.condition = condition; this.typeHandler = null; this.noValue = true; } protected Criterion(String condition, Object value, String typeHandler) { super(); this.condition = condition; this.value = value; this.typeHandler = typeHandler; if (value instanceof List<?>) { this.listValue = true; } else { this.singleValue = true; } } protected Criterion(String condition, Object value) { this(condition, value, null); } protected Criterion(String condition, Object value, Object secondValue, String typeHandler) { super(); this.condition = condition; this.value = value; this.secondValue = secondValue; this.typeHandler = typeHandler; this.betweenValue = true; } protected Criterion(String condition, Object value, Object secondValue) { this(condition, value, secondValue, null); } } }
2.4 生成StudentMapper.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="com.sx.kak.mapper.StudentMapper" > <resultMap id="BaseResultMap" type="com.sx.kak.po.Student" > <id column="id" property="id" jdbcType="INTEGER" /> <result column="NAME" property="name" jdbcType="VARCHAR" /> <result column="sex" property="sex" jdbcType="VARCHAR" /> <result column="age" property="age" jdbcType="VARCHAR" /> </resultMap> <sql id="Example_Where_Clause" > <where > <foreach collection="oredCriteria" item="criteria" separator="or" > <if test="criteria.valid" > <trim prefix="(" suffix=")" prefixOverrides="and" > <foreach collection="criteria.criteria" item="criterion" > <choose > <when test="criterion.noValue" > and ${criterion.condition} </when> <when test="criterion.singleValue" > and ${criterion.condition} #{criterion.value} </when> <when test="criterion.betweenValue" > and ${criterion.condition} #{criterion.value} and #{criterion.secondValue} </when> <when test="criterion.listValue" > and ${criterion.condition} <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," > #{listItem} </foreach> </when> </choose> </foreach> </trim> </if> </foreach> </where> </sql> <sql id="Update_By_Example_Where_Clause" > <where > <foreach collection="example.oredCriteria" item="criteria" separator="or" > <if test="criteria.valid" > <trim prefix="(" suffix=")" prefixOverrides="and" > <foreach collection="criteria.criteria" item="criterion" > <choose > <when test="criterion.noValue" > and ${criterion.condition} </when> <when test="criterion.singleValue" > and ${criterion.condition} #{criterion.value} </when> <when test="criterion.betweenValue" > and ${criterion.condition} #{criterion.value} and #{criterion.secondValue} </when> <when test="criterion.listValue" > and ${criterion.condition} <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," > #{listItem} </foreach> </when> </choose> </foreach> </trim> </if> </foreach> </where> </sql> <sql id="Base_Column_List" > id, NAME, sex, age </sql> <select id="selectByExample" resultMap="BaseResultMap" parameterType="com.sx.kak.po.StudentExample" > select <if test="distinct" > distinct </if> <include refid="Base_Column_List" /> from student <if test="_parameter != null" > <include refid="Example_Where_Clause" /> </if> <if test="orderByClause != null" > order by ${orderByClause} </if> </select> <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" > select <include refid="Base_Column_List" /> from student where id = #{id,jdbcType=INTEGER} </select> <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" > delete from student where id = #{id,jdbcType=INTEGER} </delete> <delete id="deleteByExample" parameterType="com.sx.kak.po.StudentExample" > delete from student <if test="_parameter != null" > <include refid="Example_Where_Clause" /> </if> </delete> <insert id="insert" parameterType="com.sx.kak.po.Student" > insert into student (id, NAME, sex, age) values (#{id,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{age,jdbcType=VARCHAR}) </insert> <insert id="insertSelective" parameterType="com.sx.kak.po.Student" > insert into student <trim prefix="(" suffix=")" suffixOverrides="," > <if test="id != null" > id, </if> <if test="name != null" > NAME, </if> <if test="sex != null" > sex, </if> <if test="age != null" > age, </if> </trim> <trim prefix="values (" suffix=")" suffixOverrides="," > <if test="id != null" > #{id,jdbcType=INTEGER}, </if> <if test="name != null" > #{name,jdbcType=VARCHAR}, </if> <if test="sex != null" > #{sex,jdbcType=VARCHAR}, </if> <if test="age != null" > #{age,jdbcType=VARCHAR}, </if> </trim> </insert> <select id="countByExample" parameterType="com.sx.kak.po.StudentExample" resultType="java.lang.Integer" > select count(*) from student <if test="_parameter != null" > <include refid="Example_Where_Clause" /> </if> </select> <update id="updateByExampleSelective" parameterType="map" > update student <set > <if test="record.id != null" > id = #{record.id,jdbcType=INTEGER}, </if> <if test="record.name != null" > NAME = #{record.name,jdbcType=VARCHAR}, </if> <if test="record.sex != null" > sex = #{record.sex,jdbcType=VARCHAR}, </if> <if test="record.age != null" > age = #{record.age,jdbcType=VARCHAR}, </if> </set> <if test="_parameter != null" > <include refid="Update_By_Example_Where_Clause" /> </if> </update> <update id="updateByExample" parameterType="map" > update student set id = #{record.id,jdbcType=INTEGER}, NAME = #{record.name,jdbcType=VARCHAR}, sex = #{record.sex,jdbcType=VARCHAR}, age = #{record.age,jdbcType=VARCHAR} <if test="_parameter != null" > <include refid="Update_By_Example_Where_Clause" /> </if> </update> <update id="updateByPrimaryKeySelective" parameterType="com.sx.kak.po.Student" > update student <set > <if test="name != null" > NAME = #{name,jdbcType=VARCHAR}, </if> <if test="sex != null" > sex = #{sex,jdbcType=VARCHAR}, </if> <if test="age != null" > age = #{age,jdbcType=VARCHAR}, </if> </set> where id = #{id,jdbcType=INTEGER} </update> <update id="updateByPrimaryKey" parameterType="com.sx.kak.po.Student" > update student set NAME = #{name,jdbcType=VARCHAR}, sex = #{sex,jdbcType=VARCHAR}, age = #{age,jdbcType=VARCHAR} where id = #{id,jdbcType=INTEGER} </update> </mapper>
2.5 编写application.yml
server: port: 8080 spring: datasource: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/db0711?characterEncoding=utf8&serverTimezone=UTC username: root password: root mybatis: type-aliases-package: po mapper-locations: classpath:mapping/*.xml
2.6 编写JsonUtils工具类
package com.sx.kak.utils; import java.util.List; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.JavaType; import com.fasterxml.jackson.databind.ObjectMapper; public class JsonUtils { // 定义jackson对象 private static final ObjectMapper MAPPER = new ObjectMapper(); /** * 将对象转换成json字符串。 * <p>Title: pojoToJson</p> * <p>Description: </p> * @param data * @return */ public static String objectToJson(Object data) { try { String string = MAPPER.writeValueAsString(data); return string; } catch (JsonProcessingException e) { e.printStackTrace(); } return null; } /** * 将json结果集转化为对象 * * @param jsonData json数据 * @param clazz 对象中的object类型 * @return */ public static <T> T jsonToPojo(String jsonData, Class<T> beanType) { try { T t = MAPPER.readValue(jsonData, beanType); return t; } catch (Exception e) { e.printStackTrace(); } return null; } /** * 将json数据转换成pojo对象list * <p>Title: jsonToList</p> * <p>Description: </p> * @param jsonData * @param beanType * @return */ public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) { JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType); try { List<T> list = MAPPER.readValue(jsonData, javaType); return list; } catch (Exception e) { e.printStackTrace(); } return null; } }
2.7 编写RedisUtils工具类
package com.sx.kak.utils; import java.util.List; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.JavaType; import com.fasterxml.jackson.databind.ObjectMapper; public class JsonUtils { // 定义jackson对象 private static final ObjectMapper MAPPER = new ObjectMapper(); /** * 将对象转换成json字符串。 * <p>Title: pojoToJson</p> * <p>Description: </p> * @param data * @return */ public static String objectToJson(Object data) { try { String string = MAPPER.writeValueAsString(data); return string; } catch (JsonProcessingException e) { e.printStackTrace(); } return null; } /** * 将json结果集转化为对象 * * @param jsonData json数据 * @param clazz 对象中的object类型 * @return */ public static <T> T jsonToPojo(String jsonData, Class<T> beanType) { try { T t = MAPPER.readValue(jsonData, beanType); return t; } catch (Exception e) { e.printStackTrace(); } return null; } /** * 将json数据转换成pojo对象list * <p>Title: jsonToList</p> * <p>Description: </p> * @param jsonData * @param beanType * @return */ public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) { JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType); try { List<T> list = MAPPER.readValue(jsonData, javaType); return list; } catch (Exception e) { e.printStackTrace(); } return null; } }
2.8 编写RedisUtils工具类的实现类
package com.sx.kak.utils; import redis.clients.jedis.Jedis; /** * Created by Kak on 2020/9/17. */ public class SingleTonRedisUtil implements RedisUtils{ private Jedis jedis; public SingleTonRedisUtil(Jedis jedis){ this.jedis = jedis; } @Override public void hset(String key, String filed, String value) { jedis.hset(key, filed, value); } @Override public String hget(String key, String field) { return jedis.hget(key, field); } }
2.9 配置初始化文件
package com.sx.kak.config; import com.sx.kak.utils.SingleTonRedisUtil; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import redis.clients.jedis.Jedis; /** * Created by Kak on 2020/9/17. */ @Configuration public class RedisConfig { @Bean public SingleTonRedisUtil singleTonRedisUtil(@Qualifier("jedis") Jedis jedis){ SingleTonRedisUtil singleTonRedisUtil = new SingleTonRedisUtil(jedis); return singleTonRedisUtil; } @Bean(name = "jedis") public Jedis getJedis(){ Jedis jedis = new Jedis("127.0.0.1",6379); return jedis; } }
2.10 配置StudentService.java
package com.sx.kak.service; import com.sx.kak.po.Student; import java.util.List; /** * Created by Kak on 2020/9/17. */ public interface StudentService { public List<Student> findAllStudent(); }
2.11 配置StudentServiceImpl.java
package com.sx.kak.service.serviceImpl; import com.sx.kak.mapper.StudentMapper; import com.sx.kak.po.Student; import com.sx.kak.po.StudentExample; import com.sx.kak.service.StudentService; import com.sx.kak.utils.JsonUtils; import com.sx.kak.utils.SingleTonRedisUtil; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List; /** * Created by Kak on 2020/9/17. */ @Service @Slf4j public class StudentServiceImpl implements StudentService { @Autowired(required = false) private StudentMapper studentMapper; //注入自定义的redis工具 @Autowired private SingleTonRedisUtil redisUtil; @Override public List<Student> findAllStudent() { //获取redis中存出的json字符串 String student = redisUtil.hget("student", "0"); if(student!=null){ log.info("get student from redis"); //json对象,封装的对象类型 List<Student> students = JsonUtils.jsonToList(student, Student.class); return students; } //创建查询模板对象 StudentExample studentExample = new StudentExample(); List<Student> students = studentMapper.selectByExample(studentExample); log.info("get student from db"); try{ //将查询的集合转化为json字符串 String s = JsonUtils.objectToJson(students); //放入redis中 redisUtil.hset("student","0",s); log.info("set data to redis"); }catch (Exception ex){ log.info(ex.getMessage()); } return students; } }
2.12 编写全查展示页面
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"/> <title>学生全查页面</title> </head> <body> <div id="findAll"> <table> <tr> <th>ID</th> <th>NAME</th> <th>SEX</th> <th>AGE</th> <th>Action</th> </tr> <tr th:each="s:${students}"> <td th:text="${s.id}"></td> <td th:text="${s.name}"></td> <td th:text="${s.sex}"></td> <td th:text="${s.age}"></td> </tr> </table> </div> </body> </html>
2.13 编写StudentController
package com.sx.kak.Controller; import com.sx.kak.po.Student; import com.sx.kak.service.StudentService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.List; /** * Created by Kak on 2020/9/17. */ @Controller public class StudentController { @Autowired(required = false) private StudentService studentService; @RequestMapping("/findStudent") public String findAllStu(Model model){ List<Student> allStudent = studentService.findAllStudent(); model.addAttribute("students",allStudent); return "showAllStudent"; } }
3. 结果
从打印出的日志可以看出,第一次访问是从数据库得到数据,然后存入redis中
第二次直接从redis中获取
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