mybatis之DAO层自动实现接口

* 使用mybatis举例，使用DAO接口方式实现
* 不需要针对接口去编写具体的实现类代码，编写映射XML文件，直接拿来使用即可。
* 1、导入jar包：mybatis和mysql-connector
* 2、mybatis配置文件：mybatis-config.xml，加载映射XML文件
* 3、编写JavaBean类，如UserBean
* 4、编写DAO接口和映射XML文件（namespace=DAO接口文件路径、id=接口方法名）

mybatis-config-dao.xml

 1 xml version="1.0" encoding="UTF-8" ?>
 2 DOCTYPE configuration
 3         PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 4         "http://mybatis.org/dtd/mybatis-3-config.dtd">
 5 <configuration>
 6     
 7     <properties resource="jdbc.properties">properties>
 8 
 9     <environments default="development">
10         <environment id="development">
11             <transactionManager type="JDBC"/>
12             <dataSource type="POOLED">
13                 <property name="driver" value="${driver}"/>
14                 <property name="url" value="${url}"/>
15                 <property name="username" value="${username}"/>
16                 <property name="password" value="${password}"/>
17             dataSource>
18         environment>
19     environments>
20 
21     
22     <mappers>
23         <mapper resource="dao/DaoMapper.xml"/>
24 
25     mappers>
26 configuration>

DaoMapper.xml

 1 xml version="1.0" encoding="UTF-8" ?>
 2 DOCTYPE mapper
 3         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5 
 6 <mapper namespace="dao.UserDao">
 7     
 8     <select id="selectOneUser" parameterType="int" resultType="bean.User">
 9         select * from user where id = #{id}
10     select>
11 
12     
13     <select id="selectAllUser" resultMap="userList">
14         select * from user
15     select>
16     <resultMap type="bean.User" id="userList">
17         <result property="id" column="id"/>
18         <result property="name" column="name"/>
19         <result property="age" column="age"/>
20     resultMap>
21 
22     <insert id="insertUser" useGeneratedKeys="true" keyProperty="id">
23         insert into user (id, name, age) values (#{id} ,#{name}, #{age})
24     insert>
25 
26     <update id="updateUser">
27       update user set name=#{name},age=#{age} where id=#{id}
28    update>
29 
30     <delete id="deleteUser">
31         delete from user where id=#{id}
32     delete>
33 
34     
35     <insert id="insertByColumns" useGeneratedKeys="true" keyProperty="id">
36         insert into user (id, name, age) values (NULL ,#{param1}, #{param2})
37     insert>
38     <insert id="insertByZhuJie" useGeneratedKeys="true" keyProperty="id">
39         insert into user (id, name, age) values (NULL ,#{name}, #{age})
40     insert>
41     <insert id="insertByMap" useGeneratedKeys="true" keyProperty="id">
42         insert into user (id, name, age) values (NULL ,#{name}, #{age})
43     insert>
44 
45 mapper>

UserDao.java

 1 package dao;
 2 
 3 import bean.User;
 4 import org.apache.ibatis.annotations.Param;
 5 
 6 
 7 import java.util.List;
 8 import java.util.Map;
 9 
10 /*
11 * 使用mybatis举例，使用DAO接口方式实现
12 * 不需要针对UserMapperI接口去编写具体的实现类代码，这个具体的实现类由MyBatis帮我们动态构建出来，我们只需要直接拿来使用即可。
13 * */
14 public interface UserDao {
15 
16     // 根据id查询单一数据
17     public User selectOneUser(int id);
18 
19     // 查询所有用户
20     public List selectAllUser();
21 
22     // 插入数据
23     public int insertUser(User user);
24 
25     // 修改用户
26     public int updateUser(User user);
27 
28     // 删除用户
29     public int deleteUser(User user);
30 
31     // 插入数据；多参数三种方式：默认Map、使用Map传参和使用注解别名
32     public int insertByColumns(String name, int age);
33     public int insertByZhuJie(@Param("name") String name, @Param("age") int age);
34     public int insertByMap(Map map);
35 
36 }

TestDao.java

  1 package dao;
  2 
  3 import bean.User;
  4 import org.apache.ibatis.io.Resources;
  5 import org.apache.ibatis.session.SqlSession;
  6 import org.apache.ibatis.session.SqlSessionFactory;
  7 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
  8 import org.junit.After;
  9 import org.junit.Before;
 10 import org.junit.Ignore;
 11 import org.junit.Test;
 12 
 13 import java.io.IOException;
 14 import java.io.InputStream;
 15 import java.util.HashMap;
 16 import java.util.List;
 17 import java.util.Map;
 18 
 19 /*
 20 * 使用mybatis举例，使用DAO接口方式实现
 21 * 不需要针对接口去编写具体的实现类代码，编写映射XML文件，直接拿来使用即可。
 22 * 1、导入jar包：mybatis和mysql-connector
 23 * 2、mybatis配置文件：mybatis-config.xml，加载映射XML文件
 24 * 3、编写JavaBean类，如UserBean
 25 * 4、编写DAO接口和映射XML文件（namespace=DAO接口文件路径、id=接口方法名）
 26 * */
 27 public class TestDao {
 28     String resource = "mybatis-config-dao.xml";
 29     SqlSessionFactory sqlSessionFactory = null;
 30     SqlSession session = null;
 31 
 32     @Before
 33     public void before() {
 34 //        System.out.println("Before");
 35         try {
 36             InputStream inputStream = Resources.getResourceAsStream(resource);
 37 //            创建工厂
 38             sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
 39 //            创建session对象
 40             session = sqlSessionFactory.openSession();
 41 
 42         } catch (IOException e) {
 43             e.printStackTrace();
 44         }
 45     }
 46 
 47     @After
 48     public void close() {
 49         session.close();
 50 //        System.out.println("After");
 51     }
 52 
 53     @Test
 54     public void testSelectOneUser() {
 55 //        接口自动实例化
 56         UserDao userDao = session.getMapper(UserDao.class);
 57 //        执行sql
 58         User user = userDao.selectOneUser(1);
 59         System.out.println(user);
 60     }
 61 
 62     //    批量查询
 63     @Test
 64     public void testSelectAllUser() {
 65 //        接口自动实例化
 66         UserDao userDao = session.getMapper(UserDao.class);
 67 //        执行sql
 68         List listUser = userDao.selectAllUser();
 69         System.out.println("记录个数：" + listUser.size());
 70         System.out.println(listUser);
 71     }
 72 
 73     //   插入数据
 74     @Ignore
 75     @Test
 76     public void testInsertUser() {
 77         UserDao userDao = session.getMapper(UserDao.class);
 78         User user = new User("AA", "29");
 79         int n = userDao.insertUser(user);
 80         session.commit();
 81         System.out.println("插入数据：" + user);
 82         System.out.println(n);
 83     }
 84 
 85     // 修改数据
 86     @Ignore
 87     @Test
 88     public void testUpdateUser() {
 89         UserDao userDao = session.getMapper(UserDao.class);
 90         User user = new User(2, "Tom5", "29");
 91         int n = userDao.updateUser(user);
 92         session.commit();
 93         System.out.println("修改数据：" + user);
 94         System.out.println(n);
 95     }
 96 
 97     // 修改数据
 98     @Ignore
 99     @Test
100     public void testDeleteUser() {
101         UserDao userDao = session.getMapper(UserDao.class);
102         User user = new User(13, "XX", "XX");
103         int n = userDao.deleteUser(user);
104         session.commit();
105         System.out.println("删除数据：" + user);
106         System.out.println(n);
107     }
108 
109     //   多参数插入数据的三种方式
110     @Ignore
111     @Test
112     public void testInsertByColumns() {
113         UserDao userDao = session.getMapper(UserDao.class);
114         String name = "insertByColumns";
115         int age = 33;
116 //        int n = userDao.insertByColumns(name, age);
117 //        int n = userDao.insertByZhuJie(name, age);
118 
119         Map map = new HashMap();
120         map.put("name", name);
121         map.put("age", age);
122         int n = userDao.insertByMap(map);
123 
124         session.commit();
125         System.out.println("插入数据name：" + name);
126         System.out.println(n);
127     }
128 
129 
130 }

 

User.java

 1 package bean;
 2 
 3 /**
 4  * 数据封装类
 5  * JavaBean
 6  */
 7 public class User {
 8     private int id;
 9     private String name;
10     private String age;
11 
12     public User() {
13 
14     }
15 
16     public User(String name, String age) {
17         this.name = name;
18         this.age = age;
19     }
20     public User(int id, String name, String age) {
21         this.id = id;
22         this.name = name;
23         this.age = age;
24     }
25 
26     public String getName() {
27         return name;
28     }
29 
30     public void setName(String name) {
31         this.name = name;
32     }
33 
34     public String getAge() {
35         return age;
36     }
37 
38     public void setAge(String age) {
39         this.age = age;
40     }
41 
42     public int getId() {
43         return id;
44     }
45 
46     public void setId(int id) {
47         this.id = id;
48     }
49 
50     @Override
51     public String toString() {
52         return "User{id：" + id + "; 姓名：" + name + "; 年龄：" + age + "}";
53     }
54 }

 

转载于:https://www.cnblogs.com/gongxr/p/8288212.html