Mybatis parameterType 与 resultMap

一、parameterType传递多个参数

默认情况只能有一个parameterType；parameterType 可以为简单类型（int . String  等），自定义pojo，hashMap...等等如果要分开传多个参数,可以使用pojo,或者hashMap也可以通过注解实现传递多个参数

1. mapper接口参数列表有多个,使用注解 param(“”), param中value是什么 , xml中就通过什么取

void insertWithManyParam(@Param("name") String name, @Param("birthday") Date date, @Param("age") int age);

1. xml中取值

    <insert id="insertWithManyParam">        INSERT user1 SET NAME = #{name},age=#{age},birthday=#{birthday}    </insert>

3.单元测试代码

    @Test    public void testManyParam() {        SqlSession sqlSession = sqlSessionFactory.openSession();        UserMapper1 mapper = sqlSession.getMapper(UserMapper1.class);        mapper.insertWithManyParam("多个参数传递", new Date(), 48);        sqlSession.commit();        sqlSession.close();    }

4.控制台日志

二、resultMap不配置个性映射，默认根据pojo属性名称映射

下面是例子：
1.User类

public class User {    private Integer id;    private String name;    private Integer age;    private Date birthday;

2.xml文件配置

    <resultMap id="testResultMap" type="user">        <id property="id" column="_id"/>        <result property="name" column="_name"/>    </resultMap>``<select id="findUserById" parameterType="Integer" resultMap="testResultMap">        SELECT a.id AS _id,a.name AS _name,a.age,a.* FROM ssm.user1 AS a WHERE id=#{id}    </select>`User类中还有birthday age属性，resultMap不配置，也可以映射成功；3.测试代码

@Testpublic void testFindById() {    SqlSession sqlSession = sqlSessionFactory.openSession();    UserMapper1 mapper = sqlSession.getMapper(UserMapper1.class);    User user = mapper.findUserById(3);    System.out.println(user);    sqlSession.close();}

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4.控制台日志

如果查询到的列存在重复字段，mybatis会自动去重