Mybatis--动态sql语句查询

1.UserMapper接口

package dao;

import domain.User;
import java.io.IOException;
import java.util.List;

public interface UserMapper {
     
     List<User> findAllByCondition(User user) throws IOException;
     List<User> findByIds(List<Integer> list);
}

2.UserMapper映射文件

动态sql语句主要通过 where if foreach等标签实现。

<mapper namespace="dao.UserMapper">
    <sql id="selectUser">select * from sys_usersql>

    <select id="findAllByCondition" resultType="domain.User" parameterType="domain.User">
        <include refid="selectUser">include>
        <where>
            <if test="id!=0">
                and id = #{id}
            if>
            <if test="username!=null">
                and username = #{username}
            if>
            <if test="password!=null">
                and password = #{password}
            if>
        where>
    select>

    <select id="findByIds" parameterType="list" resultType="domain.User">
        <include refid="selectUser">include>
        <where>
            <foreach collection="list" open="id in(" close=")" item="id" separator=",">
                #{id}
            foreach>
        where>
    select>

mapper>

3.测试

@Test
    public void daoByProxy() throws IOException {
     
        //获得核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        //获得sqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //获得UserMapper接口的实现类
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        //User user = new User();
        //user.setId(1);
        //user.setUsername("zhangsan");
        //user.setPassword("123");
//        List list = mapper.findAllByCondition(user);
//        System.out.println(list);
        List<Integer> list = new ArrayList<Integer>();
        list.add(1);
        List<User> list1 = mapper.findByIds(list);
        System.out.println(list1);
    }