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);
    
    void updateEmp(Employee employee);
    
    public List<Employee> getEmpByForeach(@Param("ids") List<Integer> ids);
    
    public List<Employee> getEmpByForeach2(List<Employee> employee);
}

<?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>
    
    update ="updateEmp"
        update tbl_employee 
        trim prefix="set" suffixOverrides=","if 
                last_name=#{lastName},if="gender!=null and gender == 0 or gender == 1"
                gender=#{gender},1)">
                email=#{email}
            trim
        where id=#{id}
    update="getEmpByForeach"
        select * from tbl_employee where id in
        foreach collection="ids" item="item_id" separator open="(" close=")"
            #{item_id}
        foreach="getEmpByForeach2"="list"="item"
            #{item.id}
        >
mapper>

 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> emps = new ArrayList<Employee>();
            Employee e1 =  Employee();
            e1.setId(1);
            Employee e2 =  Employee();
            e2.setId(2);
            emps.add(e1);
            emps.add(e2);
            List<Employee> es = mapper.getEmpByForeach2(emps);
            for(Employee e:es) {
                System.out.println(e);
            }
            openSession.commit();
        } finally {
            openSession.close();
        }
        
    }
    
}

DEBUG 01-21 16:21:28,692 ==>  Preparing: select * from tbl_employee where id in ( ?,? )   (BaseJdbcLogger.java:145) 
DEBUG 01-21 16:21:28,783 ==> Parameters: 1(Integer),2(Integer)  (BaseJdbcLogger.java:145) 
DEBUG 01-21 16:21:28,813 ==      Total: 2  (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)">=null]

public List<Employee> getEmpByForeach2(@Param("emps") List<Employee> employee);