Mybatis使用Dao代码方式CURD

Mybatis 使用Dao代码方式进行增、删、改、查。

1、Maven的pom.xml

 1 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 2     <modelVersion>4.0.0</modelVersion>
 3     <groupId>com.mcs</groupId>
 4     <artifactId>mybatis01</artifactId>
 5     <version>0.0.1-SNAPSHOT</version>
 6 
 7     <properties>
 8         <!-- Generic properties -->
 9         <java.version>1.8</java.version>
10         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
11         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
12         <!-- Custom properties -->
13         <mybatis.version>3.3.0</mybatis.version>
14     </properties>
15 
16     <dependencies>
17         <!-- junit -->
18         <dependency>
19             <groupId>junit</groupId>
20             <artifactId>junit</artifactId>
21             <scope>test</scope>
22         </dependency>
23         <!-- log4j -->
24         <dependency>
25             <groupId>log4j</groupId>
26             <artifactId>log4j</artifactId>
27         </dependency>
28         <dependency>
29             <groupId>org.slf4j</groupId>
30             <artifactId>slf4j-log4j12</artifactId>
31         </dependency>
32         <!-- 数据库连接驱动 -->
33         <dependency>
34             <groupId>mysql</groupId>
35             <artifactId>mysql-connector-java</artifactId>
36         </dependency>
37         <!-- c3p0 -->
38         <dependency>
39             <groupId>com.mchange</groupId>
40             <artifactId>c3p0</artifactId>
41         </dependency>
42 
43         <!-- mybatis -->
44         <dependency>
45             <groupId>org.mybatis</groupId>
46             <artifactId>mybatis</artifactId>
47             <version>${mybatis.version}</version>
48         </dependency>
49         <dependency>
50             <groupId>org.mybatis</groupId>
51             <artifactId>mybatis-spring</artifactId>
52             <version>1.2.3</version>
53         </dependency>
54         <dependency>
55             <groupId>org.mybatis</groupId>
56             <artifactId>mybatis-ehcache</artifactId>
57             <version>1.0.0</version>
58         </dependency>
59     </dependencies>
60 
61     <dependencyManagement>
62         <dependencies>
63             <dependency>
64                 <groupId>io.spring.platform</groupId>
65                 <artifactId>platform-bom</artifactId>
66                 <version>2.0.0.RELEASE</version>
67                 <type>pom</type>
68                 <scope>import</scope>
69             </dependency>
70         </dependencies>
71     </dependencyManagement>
72 
73     <build>
74         <finalName>mybatis</finalName>
75         <plugins>
76             <plugin>
77                 <groupId>org.apache.maven.plugins</groupId>
78                 <artifactId>maven-surefire-plugin</artifactId>
79                 <version>2.19</version>
80                 <configuration>
81                     <!-- Maven 跳过运行 Test 代码的配置 -->
82                     <skipTests>true</skipTests>
83                 </configuration>
84             </plugin>
85         </plugins>
86     </build>
87 
88 </project>

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2、配置文件

2.1、db.properties

1 jdbc.driverClass = com.mysql.jdbc.Driver
2 jdbc.jdbcUrl = jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8
3 jdbc.user = root
4 jdbc.password = root

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2.2、mybatis.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     <!-- 配置属性，加载数据库配置参数 -->
 8     <properties resource="db.properties"></properties>
 9 
10      <!-- 使用别名 -->
11     <typeAliases>
12         <!-- 为包下的所有文件设置别名，别名为类名，不分大小写 -->
13         <package name="com.mcs.entity"/>
14     </typeAliases>
15 
16     <!-- 和Spring整合后environments配置将废除 -->
17     <environments default="mysql_developer">
18         <environment id="mysql_developer">
19             <!-- mybatis使用jdbc事务管理方式 -->
20             <transactionManager type="JDBC" />
21             <!-- mybatis使用连接池方式来获取连接 -->
22             <dataSource type="POOLED">
23                 <!-- 配置与数据库交互的4个必要属性 -->
24                 <property name="driver" value="${jdbc.driverClass}" />
25                 <property name="url" value="${jdbc.jdbcUrl}" />
26                 <property name="username" value="${jdbc.user}" />
27                 <property name="password" value="${jdbc.password}" />
28             </dataSource>
29         </environment>
30     </environments>
31     
32     <!-- 加载映射文件     -->
33     <mappers>        
34         <mapper resource="com/mcs/mapper/EmployeeMapper.xml" />
35         <mapper resource="com/mcs/mapper/DepartmentMapper.xml" />
36         
37         <!-- 自动加载包下的所有映射文件 -->
38         <package name="com.mcs.mapper"/>
39     </mappers>
40 
41 </configuration>

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2.3、log4j.xml

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
 3 <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
 4     <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
 5         <layout class="org.apache.log4j.PatternLayout">
 6             <param name="ConversionPattern" 
 7                 value="%-5p %d{MM-dd HH:mm:ss,SSS} %m  (%F:%L) 
" />
 8         </layout>
 9     </appender>
10     <logger name="java.sql">
11         <level value="debug" />
12     </logger>
13     <logger name="org.apache.ibatis">
14         <level value="debug" />
15     </logger>
16     <root>
17         <level value="debug" />
18         <appender-ref ref="STDOUT" />
19     </root>
20 </log4j:configuration>

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3、MybatisUtil工具类

 1 package com.mcs.util;
 2 
 3 import java.io.IOException;
 4 import java.io.Reader;
 5 import java.sql.Connection;
 6 
 7 import org.apache.ibatis.io.Resources;
 8 import org.apache.ibatis.session.SqlSession;
 9 import org.apache.ibatis.session.SqlSessionFactory;
10 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
11 
12 /**
13  * Mybatis 工具类
14  */
15 public class MybatisUtil {
16     
17     private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
18     private static SqlSessionFactory sqlSessionFactory;
19     
20     /**
21      * 加载位于src/mybatis.xml配置文件
22      */
23     static{
24         try {
25             Reader reader = Resources.getResourceAsReader("mybatis.xml");
26             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
27         } catch (IOException e) {
28             e.printStackTrace();
29             throw new RuntimeException(e);
30         }
31     }
32     /**
33      * 禁止外界通过new方法创建 
34      */
35     private MybatisUtil(){}
36     
37     /**
38      * 获取SqlSession
39      */
40     public static SqlSession getSqlSession(){
41         //从当前线程中获取SqlSession对象
42         SqlSession sqlSession = threadLocal.get();
43         //如果SqlSession对象为空
44         if(sqlSession == null){
45             //在SqlSessionFactory非空的情况下，获取SqlSession对象
46             sqlSession = sqlSessionFactory.openSession();
47             //将SqlSession对象与当前线程绑定在一起
48             threadLocal.set(sqlSession);
49         }
50         //返回SqlSession对象
51         return sqlSession;
52     }
53     
54     /**
55      * 关闭SqlSession与当前线程分开
56      */
57     public static void closeSqlSession(){
58         //从当前线程中获取SqlSession对象
59         SqlSession sqlSession = threadLocal.get();
60         //如果SqlSession对象非空
61         if(sqlSession != null){
62             //关闭SqlSession对象
63             sqlSession.close();
64             //分开当前线程与SqlSession对象的关系，目的是让GC尽早回收
65             threadLocal.remove();
66         }
67     }
68 
69     public static void main(String[] args) {
70         Connection conn = MybatisUtil.getSqlSession().getConnection();
71         System.out.println(conn!=null?"连接成功":"连接失败");
72     }
73 }

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4、Mapper映射文件

 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="EmployeeMapper">
 4     <resultMap id="employeeResultMap" type="com.mcs.entity.Employee">
 5         <id column="id" property="id" jdbcType="INTEGER" />
 6         <result column="name" property="name" jdbcType="VARCHAR" />
 7         <result column="sex" property="sex" jdbcType="VARCHAR" />
 8         <result column="birthday" property="birthday" jdbcType="DATE" />
 9         <result column="email" property="email" jdbcType="VARCHAR" />
10         <result column="telephone" property="telephone" jdbcType="VARCHAR" />
11         <result column="cellphone" property="cellphone" jdbcType="VARCHAR" />
12         <result column="address" property="address" jdbcType="VARCHAR" />
13         <result column="department_id" property="departmentId" jdbcType="INTEGER" />
14     </resultMap>
15 
16     <!-- 新增职员，并返回插入后的ID值 -->
17     <insert id="add" keyColumn="id" keyProperty="id" useGeneratedKeys="true" parameterType="Employee">
18         insert into t_employee
19         ( name, sex, birthday, email, telephone, cellphone, address, department_id )
20         values
21         ( #{name}, #{sex}, #{birthday}, #{email}, #{telephone}, #{cellphone}, #{address}, #{departmentId} )
22     </insert>
23     
24     <update id="updateById" parameterType="Employee">
25         update t_employee
26         set name = #{name,jdbcType=VARCHAR},
27             sex = #{sex,jdbcType=VARCHAR},
28             birthday = #{birthday,jdbcType=DATE},
29             email = #{email,jdbcType=VARCHAR},
30             telephone = #{telephone,jdbcType=VARCHAR},
31             cellphone = #{cellphone,jdbcType=VARCHAR},
32             address = #{address,jdbcType=VARCHAR},
33             department_id = #{departmentId,jdbcType=INTEGER}
34         where id = #{id,jdbcType=INTEGER}
35     </update>
36     
37     <delete id="deleteById" parameterType="Integer" >
38         delete from t_employee
39         where id = #{id}
40     </delete>
41 
42     <select id="findById"  parameterType="Integer" resultMap="employeeResultMap">
43         select *
44         from t_employee
45         where id = #{id}
46     </select>
47     
48     <select id="findAll" resultMap="employeeResultMap">
49         select * 
50         from t_employee
51     </select>
52     
53 </mapper>

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5、Dao层接口

 1 package com.mcs.dao;
 2 
 3 import java.util.List;
 4 
 5 import com.mcs.entity.Employee;
 6 
 7 public interface EmployeeDao {
 8     
 9     public Employee add(Employee employee) throws Exception;
10     public void edit(Employee employee) throws Exception;
11     public void deleteById(Integer id) throws Exception;
12     public Employee findById(Integer id) throws Exception;
13     public List<Employee> findAll() throws Exception; 
14     
15 }

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6、Dao层实现类

 1 package com.mcs.dao.impl;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import org.apache.ibatis.session.SqlSession;
 7 
 8 import com.mcs.dao.EmployeeDao;
 9 import com.mcs.entity.Employee;
10 import com.mcs.util.MybatisUtil;
11 
12 public class EmployeeDaoImpl implements EmployeeDao {
13 
14     public Employee add(Employee employee) throws Exception {
15         SqlSession sqlSession = null;
16         try {
17             sqlSession = MybatisUtil.getSqlSession();
18             sqlSession.insert("EmployeeMapper.add", employee);
19             sqlSession.commit();
20         } catch (Exception e) {
21             e.printStackTrace();
22             sqlSession.rollback();
23             throw e;
24         } finally {
25             MybatisUtil.closeSqlSession();
26         }
27         return employee;
28     }
29 
30     public void edit(Employee employee) throws Exception {
31         SqlSession sqlSession = null;
32         try {
33             sqlSession = MybatisUtil.getSqlSession();
34             sqlSession.insert("EmployeeMapper.updateById", employee);
35             sqlSession.commit();
36         } catch (Exception e) {
37             e.printStackTrace();
38             sqlSession.rollback();
39             throw e;
40         } finally {
41             MybatisUtil.closeSqlSession();
42         }
43     }
44 
45     public void deleteById(Integer id) throws Exception {
46         SqlSession sqlSession = null;
47         try {
48             sqlSession = MybatisUtil.getSqlSession();
49             sqlSession.insert("EmployeeMapper.deleteById", id);
50             sqlSession.commit();
51         } catch (Exception e) {
52             e.printStackTrace();
53             sqlSession.rollback();
54             throw e;
55         } finally {
56             MybatisUtil.closeSqlSession();
57         }
58     }
59 
60     public Employee findById(Integer id) throws Exception {
61         SqlSession sqlSession = null;
62         Employee employee = new Employee();
63         try {
64             sqlSession = MybatisUtil.getSqlSession();
65             employee = sqlSession.selectOne("EmployeeMapper.findById", id);
66         } catch (Exception e) {
67             e.printStackTrace();
68             throw e;
69         } finally {
70             MybatisUtil.closeSqlSession();
71         }
72         return employee;
73     }
74 
75     public List<Employee> findAll() throws Exception {
76         SqlSession sqlSession = null;
77         List<Employee> employees = new ArrayList<Employee>();
78         try {
79             sqlSession = MybatisUtil.getSqlSession();
80             employees = sqlSession.selectList("EmployeeMapper.findAll");
81         } catch (Exception e) {
82             e.printStackTrace();
83             throw e;
84         } finally { 
85             MybatisUtil.closeSqlSession();
86         }
87         return employees;
88     }
89 
90 }

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7、测试代码

 1 package com.mcs.test;
 2 
 3 import java.util.Date;
 4 import java.util.List;
 5 
 6 import org.apache.log4j.Logger;
 7 import org.junit.Before;
 8 import org.junit.Test;
 9 
10 import com.mcs.dao.EmployeeDao;
11 import com.mcs.dao.impl.EmployeeDaoImpl;
12 import com.mcs.entity.Employee;
13 
14 public class TestEmployeeDao {
15     /**
16     * Logger for this class
17     */
18     private static final Logger logger = Logger.getLogger(TestEmployeeDao.class);
19     
20     
21     private EmployeeDao employeeDao;
22     
23     @Before
24     public void init() {
25         employeeDao = new EmployeeDaoImpl();
26     }
27     
28     @Test
29     public void testFindById() throws Exception {
30         Employee employee = employeeDao.findById(1);
31         logger.debug(employee);
32     }
33     
34     @Test
35     public void testFindAll() throws Exception {
36         List<Employee> employees = employeeDao.findAll();
37         logger.debug(employees);
38     }
39     
40     @Test
41     public void testAdd() throws Exception {
42         Employee employee = new Employee();
43         employee.setName("赵小凤");
44         employee.setSex("female");
45         employee.setBirthday(new Date());
46         employee.setEmail("xiaofeng@126.com");
47         
48         employee = employeeDao.add(employee);
49         
50         logger.debug(employee);
51     }
52     
53     @Test
54     public void testEditById() throws Exception {
55         Employee employee = employeeDao.findById(7);
56         employee.setDepartmentId(7);
57         employee.setAddress("天津");
58         
59         employeeDao.edit(employee);
60         
61         logger.debug(employee);
62     }
63     
64     @Test
65     public void testDeleteById() throws Exception {
66         Employee employee = employeeDao.findById(7);
67         
68         employeeDao.deleteById(7);
69         
70         logger.debug("已成功删除员工："  + employee.getName());
71     }
72 
73 }

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原文地址：https://www.cnblogs.com/maocs/p/5047860.html