mybatis 批量提交
简介:mybatis的批量操作减少数据库连接次数
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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;
}
demo:
@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>
三、总结:
方式一、需要修改数据库属性添加allowMutiQueries=true,例如:jdbc.url=jdbc:mysql://localhost:3306/mybatis?allowMultiQueries=true
方式二、需要开启事务提交,在applcationContext.xml中添加BATCH