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MyBatis动态SQL之项目准备
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1 DAO

public interface MemberDao {
    public int add(Member member);
}

2 映射

<typeAliases>
    <typeAlias type="cn.tedu.dynamic.pojo.Member" alias="Member" />
</typeAliases>

<mappers>
    <mapper resource="mappers/MemberMapper.xml" />
</mappers>

<mapper namespace="cn.tedu.dynamic.dao.MemberDao">
    ...
    <insert id="add">
        insert into t_member(nick, gender, age, city)
        values(#{nick}, #{gender}, #{age}, #{city})
    </insert>
    ...
</mapper>

3 测试

public class MemberDaoTest {
    ...
    @Test
    public void testAdd() {
        MemberDao dao = MyBatisUtil.getMapper(MemberDao.class);
        assertEquals(1, dao.add(new Member(0, "john", "男", 20, "北京")));
        assertEquals(1, dao.add(new Member(0, "thomas", "男", 35, "上海")));
        assertEquals(1, dao.add(new Member(0, "luck", "男", 40, "广州")));
        assertEquals(1, dao.add(new Member(0, "lily", "女", 25, "北京")));
        assertEquals(1, dao.add(new Member(0, "susan", "女", 30, "上海")));
    }
    ...
}

运行测试用例。

例程：Dynamic

4 查询

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class SearchParams {
    private String gender;
    private Integer minAge;
    private Integer maxAge;
    private String city;
}

public interface MemberDao {
    ...
    //public List<Member> search(HashMap<String, Object> params);
    public List<Member> search(SearchParams params);
    ...
}

在多条件查询时，如果条件的个数和内容不确定，可将参数指定为HashMap或其它可用于封装查询条件的实体类型。

public class MemberDaoTest {
    ...
    @Test
    public void testSearch() {
        MemberDao dao = MyBatisUtil.getMapper(MemberDao.class);
        /*
        HashMap<String, Object> params = new HashMap<>();
        params.put("gender", "女");
        params.put("minAge", 20);
        params.put("maxAge", 30);
        params.put("city", "北京");
        */
        SearchParams params = new SearchParams("女", 20, 30, "北京");
        List<Member> members = dao.search(params);
        System.out.println(members);
    }
    ...
}

例程：Dynamic