springboot+mybatis简单实例

springboot整合mybatis

SpringBoot简介:
核心
1、pom.xml,通过依赖引入jar包,不必再自己下载什么的。由maven统一管理。
2、由java自身的class加载配置信息,而不是通过.xml的配置文件加载。
3、自身有Tomcat,启动由自身的被@SpringBootApplication 注解的main程序入口,而不是启动Tomcat等等。

mybatis简介(是一个支持动态Sql语句的持久层框架):
核心
1、Mapper.xml,由Mapper.xml文件与数据库映射,表、字段一一对应,然后写出需要执行的SQL语句。
2、Mapper接口,由java写的Mapper接口与Mapper.xml文件对应(接口的方法与.xml的SQL语句一一对应)

数据库中表格为Xuser,只有三个字段:xuser_id、xuser_age、xuser_name
源代码:
https://github.com/mengyuxiaofeng/SpringBoot
项目结构如下:
springboot+mybatis简单实例
一、pom.xml中加入需要的jar包依赖
核心的依赖如下
SpringBoot核心
springboot+mybatis简单实例
SpringBoot的web
springboot+mybatis简单实例
mybatis的依赖
springboot+mybatis简单实例
连接数据库MySQL的依赖
springboot+mybatis简单实例
具体的pom.xml文件如下:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.huoli</groupId>
  <artifactId>SpringBootDemo</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>SpringBootDemo Maven Webapp</name>
  <url>http://maven.apache.org</url>
  
  <parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.6.RELEASE</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </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>1.3.1</version>
	</dependency>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-devtools</artifactId>
		<optional>true</optional>
	</dependency> 
	
	<dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-web</artifactId>
	</dependency>


    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>
    
    <dependency>
	  <groupId>javax.servlet</groupId>
	  <artifactId>jstl</artifactId>
    </dependency> 
    <dependency>
	  <groupId>org.apache.tomcat.embed</groupId>
	  <artifactId>tomcat-embed-jasper</artifactId>
	  <scope>provided</scope>
    </dependency>
  </dependencies>
  <build>
    <finalName>SpringBootDemo</finalName>
    
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
  </build>
</project>

二、配置连接数据库(JDBC)的参数,以及mybatis的Mapper.xml的位置
具体的application.yml如下:

spring:
  datasource:
    url: jdbc:mysql://221.235.53.167:3306/gttest?characterEncoding=utf8
    username: gttest
    password: gttest0319
    driver-class-name: com.mysql.jdbc.Driver
    
mybatis:
  mapper-locations: classpath:mapper/*.xml

三、建立实体Xuser
Xuser如下:

package com.huoli.demo.entity;

import java.io.Serializable;

public class Xuser  implements Serializable{
	private int id;

	private String name;

	private int age;

	public int getId()
	{
		return id;
	}

	public String getName()
	{
		return name;
	}

	public int getAge()
	{
		return age;
	}

	public void setId(int id)
	{
		this.id = id;
	}

	public void setName(String name)
	{
		this.name = name;
	}

	public void setAge(int age)
	{
		this.age = age;
	}
}

四、通过XuserMapper接口、XuserMapper.xml、DataSourceConfig实现数据库操作(核心)

连接数据库是由DataSourceConfig实现,它实例化了一个DataSource。整个DataSourceConfig相当于一个.xml的配置文件,类似于以前的applicationContext.xml。
如下:

package com.huoli.demo.config;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.apache.tomcat.jdbc.pool.DataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class DataSourceConfig {
	@ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource dataSource(){
       return new DataSource();
    }
}

对数据库的增删改查操作是通过XuserMapper.xml实现的。
有两个需要注意的地方:namespace以及type
namespace指明了对应的XuserMapper接口:

<mapper namespace="com.huoli.demo.Mapper.XuserMapper" >

type指明了对应的实体Xuser

<resultMap id="BaseResultMap" type="com.huoli.demo.entity.Xuser" >

具体如下

<?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.huoli.demo.Mapper.XuserMapper" >
    <resultMap id="BaseResultMap" type="com.huoli.demo.entity.Xuser" >
        <id column="xuser_id" property="id" jdbcType="BIGINT" />
        <result column="xuser_name" property="name" jdbcType="VARCHAR" />
        <result column="xuser_age" property="age" jdbcType="BIGINT" />
    </resultMap>
     
    <sql id="Base_Column_List" >
        xuser_id, xuser_name, xuser_age
    </sql>
 
    <select id="getAll" resultMap="BaseResultMap"  >
       SELECT
       <include refid="Base_Column_List" />
       FROM xuser
    </select>
 
    <select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >
        SELECT
       <include refid="Base_Column_List" />
       FROM xuser
       WHERE id = #{id}
    </select>
 
    <insert id="insert" >
       INSERT INTO
            xuser
            (xuser_id,xuser_name,xuser_age)
        VALUES
            (#{id}, #{name}, #{age})
    </insert>
     
    <delete id="delete" parameterType="java.lang.Long" >
       DELETE FROM
             xuser
       WHERE
             xuser_id =#{id}
    </delete>
 
</mapper>

最后的XuserMapper接口是Controller调用的,XuserController是没法直接调用XuserMapper.xml中的方法,必须调用XuserMapper接口中的方法,而XuserMapper接口中的方法是与XuserMapper.xml中的方法一一对应的。
具体如下:

package com.huoli.demo.Mapper;

import java.util.List;

import org.apache.ibatis.annotations.Mapper;

import com.huoli.demo.entity.Xuser;

@Mapper
public interface XuserMapper {
	List<Xuser> getAll();
    
    Xuser getOne(Long id);
 
    void insert(Xuser user);
 
    void update(Xuser user);
 
    void delete(Long id);
}

五、建立XuserController实现页面交互
具体如下:

package com.huoli.demo.controller;

import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;

import com.huoli.demo.Mapper.XuserMapper;
import com.huoli.demo.entity.Xuser;

@RestController
public class XuserController {
	@Autowired
    private XuserMapper xuserMapper;
	
	@RequestMapping("getUsers")
    public List<Xuser> getUsers() {
        List<Xuser> users=xuserMapper.getAll();
        return users;
    }
     
    @RequestMapping("getUser")
    public Xuser getUser(Long id) {
    	Xuser user=xuserMapper.getOne(id);
        return user;
    }
     
    @RequestMapping("add")
    public void save(Xuser user) {
        xuserMapper.insert(user);
    }
     
//    @RequestMapping(value="update")
//    public void update(Xuser user) {
//        xuserMapper.update(user);
//    }
     
    @RequestMapping(value="delete/{id}")
    public void delete(@PathVariable("id") Long id) {
        xuserMapper.delete(id);
    }
    
    @RequestMapping(value = "hello", method = RequestMethod.GET)
    public String hello(Map<String,Object> map){   
    return "饶你吗";
    }
}

六、通过Start.class(被@SpringBootApplication注释的含有main的启动类)发布,就像运行一个简单的程序一样。运行@SpringBootApplication注释的main函数就行了。

package com.huoli.demo;

import java.util.Map;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@SpringBootApplication
@SpringBootConfiguration
@EnableAutoConfiguration
//@ComponentScan("controller")
//@ComponentScan(basePackages = {"com.huoli.demo.controller"}) 
public class Start {
	@RequestMapping("hello1")
	@ResponseBody
    public String hello(Map<String,Object> map){   
    return "饶你吗1";
    }
	
	public static void main(String[] args) {
		SpringApplication.run(Start.class, "--server.port=9999");//后面是直接设置端口号
	}
}

七、在浏览器中查看
在浏览器中输入:
http://localhost:9999/getUsers

可以得到页面:
springboot+mybatis简单实例