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JDBC Template

分类: 文章 • 2023-03-22 12:21:40

JDBC Template

一.简化持久化操纵，Spring在JDBC API之上提供了JDBC Template组件
传统：

JDBC Template


JDBC Template：
JDBC Template

/*JDBC Template提供统一的模板方法，在保留代码灵活性的基础上尽量减少持久化代码*/

/*jabc api*/
Statement statement=conn.createStatement();
ResultSet resultSet=statement.executeQuery("select count(*) COUNT form student");
if(resultSet.next){
	Integer count =resultSet.getInt("COUNT")；
  }


/*JDBC Template*/
Integer count=jt.queryFoeObject("select count(*) COUNT form student",Inter.class);

二.JDBC配置：

  • Maven：依赖
    • mysql驱动
    • Spring组件（core、beans、context、aop）
    • JDBC Template（jdbc，tx）
  • Spring配置
    • 数据源
    • JDBC Template

/* XML配置spring.xml */

/* 数据源*/
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="username" value="root"></property>
        <property name="password" value="密码"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/newtest"></property>
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
</bean>

/*工具类*/
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
</bean>

三.JDBC Templetate基本使用

  • execute方法

  • update与batchUpdate方法

  • query与queryXXX方法

    • JDBC Template

  • call方法

public class Test{
 	@Test
  private JdbcTemplate jdbcTemplate;
  {
    ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
    JdbcTemplate jdbcTemplate=(JdbcTemlate)context.getBean("jdbcTemplate");
  }
   @Test
  public void testExecute(){
    jdbcTemplate.execute("create table user(id int, name varchar(20))");
  }
   @Test
  public void testUpdate1(){
		String sql="insert into student(name,sex)value(?,?)";
    jdbcTemplate.update(sql,new Object[]{"张三","男"})
  }
   @Test
  public void testUpdate2(){
		String sql="update student set sex=? where id=?";
    jdbcTemplate.update(sql,"女","1003") //参数自定不需要封装成object数组类型
  }
  /* 批量*/
   @Test
  public void testbathUpdate(){
  	 String[] sqls={
     		"insert into student(name,sex)value("张三","男")",，
        "insert into student(name,sex)value("五斯","男")",
        "insert into student(name,sex)value("李司","男")",
        "update student set sex='女' where id=2001"
     };
    jdbcTemplate.bathUpdate(sqls);
  }
  @Test
  public void testBatchUpdate2(){
  	String sql="insert into selectiont(student,course)value(?,?)";
    Llist<object[]> list=new ArrayList<Object[]>();
    list.add(new Object[]{1005,1001});
    list.add(new Object[]{1005,1003});
    jcbcTemplate.batchUpdate(sql,list);
  }
  @Test
  public void testQuery1(){
  	String sql="select count(*) form student";
    int count=jdbcTemplate.queryForObject(sql,Integer.class);
    System.out.println(count);
  }
  @Test
   public void testQuery2(){
  	String sql="select name form student whre sex=?";
    List<String>names=jdbcTemplate.queryForList(sql,String.class,...args:"男");
    System.out.println(name);
  @Test
   public void testQuerymap1(){
  	String sql="select count(*) form student whre id=?";
    Map<String,Object> stu=jdbcTemplate.queryForMap(sql,...args:"1003");
    System.out.println(stu);
  }
   
   @Test
   public void testQuerymap3(){
  	String sql="select count(*) form student ";
    List<Map<String,Object>> stu=jdbcTemplate.queryForMap(sql);
    System.out.println(stu);
  }
  
  @Test  /*查询一个实体对象*/
  public void testQueryEntity1(){
        String sql = "select * from student where id = ?";
        Student stu = jdbcTemplate.queryForObject(sql, new StudentRowMapper(), 1004);
        System.out.println(stu);
  }
    
   @Test  /*查询多个实体对象*/
   public void testQueryEntity2(){
        String sql = "select * from student";
        List<Student> stus = jdbcTemplate.query(sql,new StudentRowMapper());
        System.out.println(stus);
    }
     
    private class StudentRowMapper implements RowMapper<Student>{
        public Student mapRow(ResultSet resultSet, int i) throws SQLException {
            Student stu = new Student();
            stu.setId(resultSet.getInt("id"));
            stu.setName(resultSet.getString("name"));
            stu.setSex(resultSet.getString("sex"));
            stu.setBorn(resultSet.getDate("born"));
            return stu;
        }
    }

}

四.JDBC Template持久层
-实体类
-DAO
-注入JdbcTemplate
-声明RowMapper

  • 学生实现类
package com.imooc.sc.dao.impl;

import com.imooc.sc.dao.StudentDao;
import com.imooc.sc.entity.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

@Repository
public class StudentDaoImpl implements StudentDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void insert(Student stu) {
        String sql = "insert into student(name,sex,born) values(?,?,?)";
        jdbcTemplate.update(sql,stu.getName(),stu.getSex(),stu.getBorn());
    }

    public void update(Student stu) {
        String sql = "update student set name=?,sex=?,born=? where id=?";
        jdbcTemplate.update(sql,stu.getName(),stu.getSex(),stu.getBorn(),stu.getId());
    }

    public void delete(int id) {
        String sql = "delete from student where id=?";
        jdbcTemplate.update(sql,id);
    }

    public Student select(int id) {
        String sql = "select * from student where id=?";
        return jdbcTemplate.queryForObject(sql,new StudentRowMapper(),id);
    }

    public List<Student> selectAll() {
        String sql = "select * from student";
        return jdbcTemplate.query(sql,new StudentRowMapper());
    }

    private class StudentRowMapper implements RowMapper<Student> {
        public Student mapRow(ResultSet resultSet, int i) throws SQLException {
            Student stu = new Student();
            stu.setId(resultSet.getInt("id"));
            stu.setName(resultSet.getString("name"));
            stu.setSex(resultSet.getString("sex"));
            stu.setBorn(resultSet.getDate("born"));
            return stu;
        }
    }
}
  • 课程实现类
package com.imooc.sc.dao.impl;

import com.imooc.sc.dao.CourseDao;
import com.imooc.sc.entity.Course;
import com.imooc.sc.entity.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
@Repository
public class CourseDaoImpl implements CourseDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void insert(Course course) {
        String sql = "insert into course(name,score) values(?,?)";
        jdbcTemplate.update(sql,course.getName(),course.getScore());
    }

    public void update(Course course) {
        String sql = "update course set name=?,score=? where id=?";
        jdbcTemplate.update(sql,course.getName(),course.getScore(),course.getId());
    }

    public void delete(int id) {
        String sql = "delete from course where id=?";
        jdbcTemplate.update(sql,id);
    }

    public Course select(int id) {
        String sql = "select * from course where id=?";
        return jdbcTemplate.queryForObject(sql,new CourseRowMapper(),id);
    }

    public List<Course> selectAll() {
        String sql = "select * from course";
        return jdbcTemplate.query(sql,new CourseRowMapper());
    }
    private class CourseRowMapper implements RowMapper<Course> {
        public Course mapRow(ResultSet resultSet, int i) throws SQLException {
            Course course = new Course();
            course.setId(resultSet.getInt("id"));
            course.setName(resultSet.getString("name"));
            course.setScore(resultSet.getInt("score"));
            return course;
        }
    }
}
  • 选课实现类
package com.imooc.sc.dao.impl;

import com.imooc.sc.dao.SelectionDao;
import com.imooc.sc.entity.Selection;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
@Repository
public class SelectionDaoImpl implements SelectionDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void insert(List<Selection> seles) {
        String sql = "insert into selection values(?,?,?,?)";
        List<Object[]> list = new ArrayList<Object[]>();
        for(Selection sel:seles){
            Object[] args = new Object[4];
            args[0] = sel.getSid();
            args[1]=sel.getCid();
            args[2] = sel.getSelTime();
            args[3] =sel.getScore();
            list.add(args);
        }
        jdbcTemplate.batchUpdate(sql,list);
    }

    public void delete(int sid,int cid) {
        String sql = "delete from selection where student=? and course=?";
        jdbcTemplate.update(sql,sid,cid);
    }

    public List<Map<String, Object>> selectByStudent(int sid) {
        String sql = "select se.*,stu.name sname,cou.name cname from selection se " +
                "left join student stu on se.student=stu.id " +
                "left join course cou on se.course=cou.id" +
                "where student=?";
        return jdbcTemplate.queryForList(sql,sid);
    }

    public List<Map<String, Object>> selectByCourse(int cid) {
        String sql = "select se.*,stu.name sname,cou.name cname from selection se " +
                "left join student stu on se.student=stu.id " +
                "left join course cou on se.course=cou.id" +
                "where course=?";
        return jdbcTemplate.queryForList(sql,cid);
    }
}

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