mybatis动态sql之遍历集合(学习foreach标签(初探))
发布时间:2020-12-14 18:02:27 所属栏目:大数据 来源:网络整理
导读:EmployeeMapperDynamicSql.java package com.gong.mybatis.mapper; import java.util.List; java.util.Map; org.apache.ibatis.annotations.MapKey; org.apache.ibatis.annotations.Param; com.gong.mybatis.bean.Employee; public interface EmployeeMapper
EmployeeMapperDynamicSql.java package com.gong.mybatis.mapper; import java.util.List; java.util.Map; org.apache.ibatis.annotations.MapKey; org.apache.ibatis.annotations.Param; com.gong.mybatis.bean.Employee; public interface EmployeeMapperDynamicSql { public List<Employee> getEmpByConditionIf(Employee employee); public List<Employee> getEmpByForeach(@Param("ids") List<Integer> ids); } EmployeeMapperDynamicSql.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.gong.mybatis.mapper.EmployeeMapperDynamicSql"> <!-- 查询,要查那个就带上那个条件 --> select id="getEmpByConditionIf" resultType="com.gong.mybatis.bean.Employee"> select * from tbl_employee where> choose> when test="id!=null" id=#{id} </when="lastName!=null" last_name like #{lastName} ="email!=null" email=#{email} otherwise> select> ="getEmpByForeach" select * from tbl_employee where id in foreach collection="ids" item="item_id" separator="," open="(" close=")" #{item_id} foreach> mapper> 说明:
也就是说整个sql语句是这样的:select * from tbl_employee where id in (1,3) 注意的是我们在接口中定义了传入参数的名称,因此在collection中可以传入该名称。 进行测试: com.gong.mybatis.test; java.io.IOException; java.io.InputStream; java.util.ArrayList; java.util.Arrays; org.apache.ibatis.io.Resources; org.apache.ibatis.session.SqlSession; org.apache.ibatis.session.SqlSessionFactory; org.apache.ibatis.session.SqlSessionFactoryBuilder; org.junit.Test; com.gong.mybatis.bean.Employee; com.gong.mybatis.mapper.EmployeeMapperDynamicSql; class TestMybatis3 { public SqlSessionFactory getSqlSessionFactory() throws IOException { String resource = "mybatis-config.xml"; InputStream is = Resources.getResourceAsStream(resource); return new SqlSessionFactoryBuilder().build(is); } @Test void test() IOException { SqlSessionFactory sqlSessionFactory = getSqlSessionFactory(); SqlSession openSession = sqlSessionFactory.openSession(); try { EmployeeMapperDynamicSql mapper = openSession.getMapper(EmployeeMapperDynamicSql.); List<Employee> es = mapper.getEmpByForeach(Arrays.asList(1,3)); for(Employee e:es) { System.out.println(e); } openSession.commit(); } finally { openSession.close(); } } } 最终结果: DEBUG 01-21 15:31:16,176 ==> Preparing: select * from tbl_employee where id in ( ?,?,? ) (BaseJdbcLogger.java:145) DEBUG 01-21 15:31:16,241 ==> Parameters: 1(Integer),2(Integer),3(Integer) (BaseJdbcLogger.java:145) DEBUG 01-21 15:31:16,335 == Total: 3 (BaseJdbcLogger.java:145) Employee [id=1,lastName=dema,1)">genderemail=dema@qq.com,1)">dept=null] Employee [id=2,1)">=jack,1)">=675544321@qq.com,1)">=3,1)">=小红,1)">=0,1)">=xiaohong@qq.com,1)">=null] (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |