Mybatis进阶学习笔记——输出映射

1     <!-- 统计记录数 -->
2     <select id="queryTotalCount" resultType="long">
3         SELECT COUNT(*) FROM t_customer
4     </select>

    /**
     * 输出映射
     */
    @Test
    public void test2() {
        SqlSession sqlSession = SessionUtils.getSession();
        // getMapper(): 返回指定接口的动态代理的实现类对象
        CustomerDao dao = sqlSession.getMapper(CustomerDao.class);
        Long count = dao.queryTotalCount();
        System.out.println(count);
        sqlSession.commit();
        sqlSession.close();
    }

1     <select id="queryCustomer" parameterType="int" resultType="Customer">
2         SELECT * FROM t_customer WHERE id=#{value}
3     </select>

 1     /**
 2      * 输出映射
 3      */
 4     @Test
 5     public void test2() {
 6         SqlSession sqlSession = SessionUtils.getSession();
 7         // getMapper(): 返回指定接口的动态代理的实现类对象
 8         CustomerDao dao = sqlSession.getMapper(CustomerDao.class);
 9         Customer c = dao.queryCustomer(1);
10         System.out.println(c);
11         sqlSession.commit();
12         sqlSession.close();
13     }

 1     <!-- 定义ResultMap -->
 2     <!-- 
 3         含义说明：
 4         type：我们需要封装成的实体类
 5         id：定义的名称，供下方代码使用
 6      -->
 7     <resultMap type="CustomerRM" id="customerResultMap">
 8         <!-- 
 9             id：映射主键
10             column：数据库字段
11             property：实体类中的命名
12          -->
13         <id column="id" property="custId"/>
14         <result column="name" property="custName"/>
15         <result column="gender" property="custGender"/>
16         <result column="telephone" property="custTelephone"/>
17     </resultMap>

1     <select id="queryCustomerResultMap" parameterType="int" resultMap="customerResultMap">
2     <!-- resultMap：方法的返回值类型，也就是上方定义的type="CustomerRM"中的CustomerRM对象 -->
3         SELECT * FROM t_customer WHERE id=#{value}
4     </select>

 1     /**
 2      * 输出映射
 3      */
 4     @Test
 5     public void test2() {
 6         SqlSession sqlSession = SessionUtils.getSession();
 7         // getMapper(): 返回指定接口的动态代理的实现类对象
 8         CustomerDao dao = sqlSession.getMapper(CustomerDao.class);
 9         CustomerRM c =  dao.queryCustomerResultMap(1);
10         System.out.println(c);
11         sqlSession.commit();
12         sqlSession.close();
13     }

 1 package cn.sm1234.domain;
 2 
 3 public class CustomerRM {
 4 
 5     private Integer custId;
 6     private String custName;
 7     private String custGender;
 8     private String custTelephone;
 9     public Integer getCustId() {
10         return custId;
11     }
12     public void setCustId(Integer custIid) {
13         this.custId = custIid;
14     }
15     public String getCustName() {
16         return custName;
17     }
18     public void setCustName(String custName) {
19         this.custName = custName;
20     }
21     public String getCustGender() {
22         return custGender;
23     }
24     public void setCustGender(String custGender) {
25         this.custGender = custGender;
26     }
27     public String getCustTelephone() {
28         return custTelephone;
29     }
30     public void setCustTelephone(String custTelephone) {
31         this.custTelephone = custTelephone;
32     }
33     @Override
34     public String toString() {
35         return "CustomerRM [custId=" + custId + ", custName=" + custName + ", custGender=" + custGender
36                 + ", custTelephone=" + custTelephone + "]";
37     }
38     
39 }