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MyBatis框架的使用及源码分析(一) 配置与使用

我们先来看一个例子，简单的了解一下mybatis的mapper接口方式的使用。

 1 package org.mybatis.spring.sample;
 2 
 3 import org.apache.ibatis.io.Resources;
 4 import org.apache.ibatis.session.SqlSession;
 5 import org.apache.ibatis.session.SqlSessionFactory;
 6 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 7 import org.junit.Test;
 8 import org.mybatis.spring.sample.bean.User;
 9 import org.mybatis.spring.sample.mapper.UserMapper;
10 
11 import java.io.IOException;
12 
13 public class MybatisTest {
14 
15     /**
16      * 读取mybatis的配置文件，生成SqlSessionFactory
17      *
18      * @return
19      */
20     private static SqlSessionFactory getSessionFactory() {
21         SqlSessionFactory sessionFactory = null;
22         String resource = "mybatisConfig.xml";
23         try {
24             sessionFactory = new SqlSessionFactoryBuilder().build(Resources
25                     .getResourceAsReader(resource));
26         } catch (IOException e) {
27             e.printStackTrace();
28         }
29         return sessionFactory;
30     }
31 
32     @Test
33     public void findUserById() {
34         SqlSessionFactory sqlSessionFactory = getSessionFactory();
35         SqlSession sqlSession = sqlSessionFactory.openSession();
36         UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
37         User user = userMapper.selectByPrimaryKey(1l);
38         System.out.println(user.getId() + " /  " + user.getName());
39     }
40 
41 }

输出结果

1 /  赵大

数据库表 user

User.java

  1 /*
  2  * User.java
  3  * Copyright(C) 2015-2017 Jstudio.org
  4  * All rights reserved.
  5  * --------------------------------------
  6  * 2017-09-17 Created.
  7  */
  8 package org.mybatis.spring.sample.bean;
  9 
 10 import java.io.Serializable;
 11 
 12 /**
 13  *
 14  * This class was generated by MyBatis Generator.
 15  * This class corresponds to the database table user
 16  *
 17  * @mbg.generated do_not_delete_during_merge 2017-09-17
 18  */
 19 public class User implements Serializable {
 20     /**
 21      * 主键
 22      */
 23     private Long id;
 24 
 25     /**
 26      * 用户名
 27      */
 28     private String name;
 29 
 30     /**
 31      * 密码
 32      */
 33     private String password;
 34 
 35     /**
 36      * 电子邮件
 37      */
 38     private String email;
 39 
 40     /**
 41      * 年龄
 42      */
 43     private Integer age;
 44 
 45     private static final long serialVersionUID = 1L;
 46 
 47     /**
 48      * 获取主键
 49      *
 50      * @return id - 主键
 51      */
 52     public Long getId() {
 53         return id;
 54     }
 55 
 56     /**
 57      * 设置主键
 58      *
 59      * @param id 主键
 60      */
 61     public void setId(Long id) {
 62         this.id = id;
 63     }
 64 
 65     /**
 66      * 获取用户名
 67      *
 68      * @return name - 用户名
 69      */
 70     public String getName() {
 71         return name;
 72     }
 73 
 74     /**
 75      * 设置用户名
 76      *
 77      * @param name 用户名
 78      */
 79     public void setName(String name) {
 80         this.name = name == null ? null : name.trim();
 81     }
 82 
 83     /**
 84      * 获取密码
 85      *
 86      * @return password - 密码
 87      */
 88     public String getPassword() {
 89         return password;
 90     }
 91 
 92     /**
 93      * 设置密码
 94      *
 95      * @param password 密码
 96      */
 97     public void setPassword(String password) {
 98         this.password = password == null ? null : password.trim();
 99     }
100 
101     /**
102      * 获取电子邮件
103      *
104      * @return email - 电子邮件
105      */
106     public String getEmail() {
107         return email;
108     }
109 
110     /**
111      * 设置电子邮件
112      *
113      * @param email 电子邮件
114      */
115     public void setEmail(String email) {
116         this.email = email == null ? null : email.trim();
117     }
118 
119     /**
120      * 获取年龄
121      *
122      * @return age - 年龄
123      */
124     public Integer getAge() {
125         return age;
126     }
127 
128     /**
129      * 设置年龄
130      *
131      * @param age 年龄
132      */
133     public void setAge(Integer age) {
134         this.age = age;
135     }
136 }

View Code

UserMapper.java

 1 /*
 2  * UserMapper.java
 3  * Copyright(C) 2015-2017 Jstudio.org
 4  * All rights reserved.
 5  * --------------------------------------
 6  * 2017-09-17 Created.
 7  */
 8 package org.mybatis.spring.sample.mapper;
 9 
10 import org.mybatis.spring.sample.bean.User;
11 
12 import java.util.List;
13 
14 public interface UserMapper {
15 
16     int insert(User entity);
17 
18     int insertSelective(User entity);
19 
20     int deleteByPrimaryKey(Long id);
21 
22     int updateByPrimaryKeySelective(User entity);
23 
24     int updateByPrimaryKey(User entity);
25 
26     User selectByPrimaryKey(Long id);
27     
28 }

View Code

UserMapper.xml

  1 <?xml version="1.0" encoding="UTF-8"?>
  2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  3 <mapper namespace="org.mybatis.spring.sample.mapper.UserMapper">
  4   <!--  This is automatically generated by MyBatis Generator on 2017-09-17. -->
  5   <resultMap id="BaseResultMap" type="org.mybatis.spring.sample.bean.User">
  6     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
  7     <id column="id" jdbcType="BIGINT" property="id" />
  8     <result column="name" jdbcType="VARCHAR" property="name" />
  9     <result column="password" jdbcType="VARCHAR" property="password" />
 10     <result column="email" jdbcType="VARCHAR" property="email" />
 11     <result column="age" jdbcType="INTEGER" property="age" />
 12   </resultMap>
 13   <sql id="Base_Column_List">
 14     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 15     id, name, password, email, age
 16   </sql>
 17   <select id="selectByPrimaryKey" parameterType="java.lang.Long" resultMap="BaseResultMap">
 18     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 19     select 
 20     <include refid="Base_Column_List" />
 21     from user
 22     where id = #{id,jdbcType=BIGINT}
 23   </select>
 24   <delete id="deleteByPrimaryKey" parameterType="java.lang.Long">
 25     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 26     delete from user
 27     where id = #{id,jdbcType=BIGINT}
 28   </delete>
 29   <insert id="insert" parameterType="org.mybatis.spring.sample.bean.User">
 30     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 31     <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Long">
 32       SELECT LAST_INSERT_ID()
 33     </selectKey>
 34     insert into user (name, password, email, 
 35       age)
 36     values (#{name,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, #{email,jdbcType=VARCHAR}, 
 37       #{age,jdbcType=INTEGER})
 38   </insert>
 39   <insert id="insertSelective" parameterType="org.mybatis.spring.sample.bean.User">
 40     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 41     <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Long">
 42       SELECT LAST_INSERT_ID()
 43     </selectKey>
 44     insert into user
 45     <trim prefix="(" suffix=")" suffixOverrides=",">
 46       <if test="name != null">
 47         name,
 48       </if>
 49       <if test="password != null">
 50         password,
 51       </if>
 52       <if test="email != null">
 53         email,
 54       </if>
 55       <if test="age != null">
 56         age,
 57       </if>
 58     </trim>
 59     <trim prefix="values (" suffix=")" suffixOverrides=",">
 60       <if test="name != null">
 61         #{name,jdbcType=VARCHAR},
 62       </if>
 63       <if test="password != null">
 64         #{password,jdbcType=VARCHAR},
 65       </if>
 66       <if test="email != null">
 67         #{email,jdbcType=VARCHAR},
 68       </if>
 69       <if test="age != null">
 70         #{age,jdbcType=INTEGER},
 71       </if>
 72     </trim>
 73   </insert>
 74   <update id="updateByPrimaryKeySelective" parameterType="org.mybatis.spring.sample.bean.User">
 75     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 76     update user
 77     <set>
 78       <if test="name != null">
 79         name = #{name,jdbcType=VARCHAR},
 80       </if>
 81       <if test="password != null">
 82         password = #{password,jdbcType=VARCHAR},
 83       </if>
 84       <if test="email != null">
 85         email = #{email,jdbcType=VARCHAR},
 86       </if>
 87       <if test="age != null">
 88         age = #{age,jdbcType=INTEGER},
 89       </if>
 90     </set>
 91     where id = #{id,jdbcType=BIGINT}
 92   </update>
 93   <update id="updateByPrimaryKey" parameterType="org.mybatis.spring.sample.bean.User">
 94     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->
 95     update user
 96     set name = #{name,jdbcType=VARCHAR},
 97       password = #{password,jdbcType=VARCHAR},
 98       email = #{email,jdbcType=VARCHAR},
 99       age = #{age,jdbcType=INTEGER}
100     where id = #{id,jdbcType=BIGINT}
101   </update>
102  </mapper>

View Code

mybatisConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/test"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="sqlmapping/UserMapper.xml"/>
    </mappers>
</configuration>

View Code

后继我们将继续讲解Mybatis如何加载配置，解析Mappper的xml,创建和使用Mapper。

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原文地址：https://www.cnblogs.com/zsg88/p/7533894.html