Mybatis批量提交实现步骤

小诸哥 2022-05-31 12:39:36 0

简介：mybatis的批量操作减少数据库连接次数

一、mapper 使用foreach 遍历

　　批量insert：

<insert id="addEmpsBatch">
   INSERT INTO emp(ename,gender,email,did)
   VALUES
   <foreach collection="emps" item="emp" separator=",">
   (#{emp.eName},#{emp.gender},#{emp.email},#{emp.dept.id})
   </foreach>
 </insert>

批量update：

<update id="updateNewStock" parameterType="java.util.List">
<foreach collection="list" item="bean" index="index" open="" close="" separator=";">
UPDATE green_beans
<set>
stock=#{bean.stock}
</set>
<where>
beanUid = #{bean.beanUid}
</where>
</foreach>
</update>

二、使用 mybatis ExecutorType.BATCH

使用步骤：

(1)在全局配置文件applcationContext.xml中加入

<!-- 配置一个可以批量执行的sqlSession -->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
      <constructor-arg name="sqlSessionFactory" ref="sqlSessionFactory"></constructor-arg>
       <constructor-arg name="executorType" value="BATCH"></constructor-arg>
     </bean>

（2）在service实现中添加：

@Autowired
 private SqlSession sqlSession;
 
 
 
//批量保存员工
 @Override
 public Integer batchEmp() {
   // TODO Auto-generated method stub
  
     //批量保存执行前时间
     long start=System.currentTimeMillis();
  
     EmployeeMapper mapper= sqlSession.getMapper(EmployeeMapper.class);
     for (int i = 0; i < 10000; i++) {
       mapper.addEmp(new Employee(UUID.randomUUID().toString().substring(0,5),"b","1"));
  
     }
     long end= System.currentTimeMillis();
     long time2= end-start;
     //批量保存执行后的时间
     System.out.println("执行时长"+time2); 
   return (int) time2;
    
 }

示例：

@Test //批量保存方法测试
  public void testBatch() throws IOException{
    SqlSessionFactory sqlSessionFactory=getSqlSessionFactory();
    //可以执行批量操作的sqlSession
    SqlSession openSession=sqlSessionFactory.openSession(ExecutorType.BATCH);
     
    //批量保存执行前时间
    long start=System.currentTimeMillis();
    try{
    EmployeeMapper mapper=  openSession.getMapper(EmployeeMapper.class);
    for (int i = 0; i < 1000; i++) {
      mapper.addEmp(new Employee(UUID.randomUUID().toString().substring(0,5),"b","1"));
    }  
     
     openSession.commit();
    long end= System.currentTimeMillis();
    //批量保存执行后的时间
    System.out.println("执行时长"+(end-start));
    //批量 预编译sql一次==》设置参数==》10000次==》执行1次  677
    //非批量 （预编译=设置参数=执行 ）==》10000次  1121
     
    }finally{
      openSession.close();
    }
  }

mapper：

public interface EmployeeMapper {  
  //批量保存员工
  public Long addEmp(Employee employee);
  }

mapper.xml ：

<mapper namespace="com.agesun.mybatis.dao.EmployeeMapper"
   <!--批量保存员工 -->
  <insert id="addEmp">
    insert into employee(lastName,email,gender)
    values(#{lastName},#{email},#{gender})
  </insert>
</mapper>