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

 <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">
     <modelVersion>4.0.</modelVersion>
     <groupId>com.mcs</groupId>
     <artifactId>mybatis01</artifactId>
     <version>0.0.-SNAPSHOT</version>

     <properties>
         <!-- Generic properties -->
         <java.version>1.8</java.version>
         <project.build.sourceEncoding>UTF-</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-</project.reporting.outputEncoding>
         <!-- Custom properties -->
         <mybatis.version>3.3.</mybatis.version>
     </properties>

     <dependencies>
         <!-- junit -->
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <scope>test</scope>
         </dependency>
         <!-- log4j -->
         <dependency>
             <groupId>log4j</groupId>
             <artifactId>log4j</artifactId>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-log4j12</artifactId>
         </dependency>
         <!-- 数据库连接驱动 -->
         <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>
         </dependency>
         <!-- c3p0 -->
         <dependency>
             <groupId>com.mchange</groupId>
             <artifactId>c3p0</artifactId>
         </dependency>

         <!-- mybatis -->
         <dependency>
             <groupId>org.mybatis</groupId>
             <artifactId>mybatis</artifactId>
             <version>${mybatis.version}</version>
         </dependency>
         <dependency>
             <groupId>org.mybatis</groupId>
             <artifactId>mybatis-spring</artifactId>
             <version>1.2.</version>
         </dependency>
         <dependency>
             <groupId>org.mybatis</groupId>
             <artifactId>mybatis-ehcache</artifactId>
             <version>1.0.</version>
         </dependency>
     </dependencies>

     <dependencyManagement>
         <dependencies>
             <dependency>
                 <groupId>io.spring.platform</groupId>
                 <artifactId>platform-bom</artifactId>
                 <version>2.0..RELEASE</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
         </dependencies>
     </dependencyManagement>

     <build>
         <finalName>mybatis</finalName>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
                 <version>2.19</version>
                 <configuration>
                     <!-- Maven 跳过运行 Test 代码的配置 -->
                     <skipTests>true</skipTests>
                 </configuration>
             </plugin>
         </plugins>
     </build>

 </project>

2、配置文件

2.1、db.properties

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

2.2、mybatis.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>

     <!-- 配置属性，加载数据库配置参数 -->
     <properties resource="db.properties"></properties>

      <!-- 使用别名 -->
     <typeAliases>
         <!-- 为包下的所有文件设置别名，别名为类名，不分大小写 -->
         <package name="com.mcs.entity"/>
     </typeAliases>

     <!-- 和Spring整合后environments配置将废除 -->
     <environments default="mysql_developer">
         <environment id="mysql_developer">
             <!-- mybatis使用jdbc事务管理方式 -->
             <transactionManager type="JDBC" />
             <!-- mybatis使用连接池方式来获取连接 -->
             <dataSource type="POOLED">
                 <!-- 配置与数据库交互的4个必要属性 -->
                 <property name="driver" value="${jdbc.driverClass}" />
                 <property name="url" value="${jdbc.jdbcUrl}" />
                 <property name="username" value="${jdbc.user}" />
                 <property name="password" value="${jdbc.password}" />
             </dataSource>
         </environment>
     </environments>

     <!-- 加载映射文件     -->
     <mappers>
         <mapper resource="com/mcs/mapper/EmployeeMapper.xml" />
         <mapper resource="com/mcs/mapper/DepartmentMapper.xml" />

         <!-- 自动加载包下的所有映射文件 -->
         <package name="com.mcs.mapper"/>
     </mappers>

 </configuration>

2.3、log4j.xml

 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
 <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
     <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
         <layout class="org.apache.log4j.PatternLayout">
             <param name="ConversionPattern"
                 value="%-5p %d{MM-dd HH:mm:ss,SSS} %m  (%F:%L) \n" />
         </layout>
     </appender>
     <logger name="java.sql">
         <level value="debug" />
     </logger>
     <logger name="org.apache.ibatis">
         <level value="debug" />
     </logger>
     <root>
         <level value="debug" />
         <appender-ref ref="STDOUT" />
     </root>
 </log4j:configuration>

3、MybatisUtil工具类

 package com.mcs.util;

 import java.io.IOException;
 import java.io.Reader;
 import java.sql.Connection;

 import org.apache.ibatis.io.Resources;
 import org.apache.ibatis.session.SqlSession;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.apache.ibatis.session.SqlSessionFactoryBuilder;

 /**
  * Mybatis 工具类
  */
 public class MybatisUtil {

     private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
     private static SqlSessionFactory sqlSessionFactory;

     /**
      * 加载位于src/mybatis.xml配置文件
      */
     static{
         try {
             Reader reader = Resources.getResourceAsReader("mybatis.xml");
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
         } catch (IOException e) {
             e.printStackTrace();
             throw new RuntimeException(e);
         }
     }
     /**
      * 禁止外界通过new方法创建
      */
     private MybatisUtil(){}

     /**
      * 获取SqlSession
      */
     public static SqlSession getSqlSession(){
         //从当前线程中获取SqlSession对象
         SqlSession sqlSession = threadLocal.get();
         //如果SqlSession对象为空
         if(sqlSession == null){
             //在SqlSessionFactory非空的情况下，获取SqlSession对象
             sqlSession = sqlSessionFactory.openSession();
             //将SqlSession对象与当前线程绑定在一起
             threadLocal.set(sqlSession);
         }
         //返回SqlSession对象
         return sqlSession;
     }

     /**
      * 关闭SqlSession与当前线程分开
      */
     public static void closeSqlSession(){
         //从当前线程中获取SqlSession对象
         SqlSession sqlSession = threadLocal.get();
         //如果SqlSession对象非空
         if(sqlSession != null){
             //关闭SqlSession对象
             sqlSession.close();
             //分开当前线程与SqlSession对象的关系，目的是让GC尽早回收
             threadLocal.remove();
         }
     }

     public static void main(String[] args) {
         Connection conn = MybatisUtil.getSqlSession().getConnection();
         System.out.println(conn!=null?"连接成功":"连接失败");
     }
 }

4、Mapper映射文件

 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 <mapper namespace="EmployeeMapper">
     <resultMap id="employeeResultMap" type="com.mcs.entity.Employee">
         <id column="id" property="id" jdbcType="INTEGER" />
         <result column="name" property="name" jdbcType="VARCHAR" />
         <result column="sex" property="sex" jdbcType="VARCHAR" />
         <result column="birthday" property="birthday" jdbcType="DATE" />
         <result column="email" property="email" jdbcType="VARCHAR" />
         <result column="telephone" property="telephone" jdbcType="VARCHAR" />
         <result column="cellphone" property="cellphone" jdbcType="VARCHAR" />
         <result column="address" property="address" jdbcType="VARCHAR" />
         <result column="department_id" property="departmentId" jdbcType="INTEGER" />
     </resultMap>

     <!-- 新增职员，并返回插入后的ID值 -->
     <insert id="add" keyColumn="id" keyProperty="id" useGeneratedKeys="true" parameterType="Employee">
         insert into t_employee
         ( name, sex, birthday, email, telephone, cellphone, address, department_id )
         values
         ( #{name}, #{sex}, #{birthday}, #{email}, #{telephone}, #{cellphone}, #{address}, #{departmentId} )
     </insert>

     <update id="updateById" parameterType="Employee">
         update t_employee
         set name = #{name,jdbcType=VARCHAR},
             sex = #{sex,jdbcType=VARCHAR},
             birthday = #{birthday,jdbcType=DATE},
             email = #{email,jdbcType=VARCHAR},
             telephone = #{telephone,jdbcType=VARCHAR},
             cellphone = #{cellphone,jdbcType=VARCHAR},
             address = #{address,jdbcType=VARCHAR},
             department_id = #{departmentId,jdbcType=INTEGER}
         where id = #{id,jdbcType=INTEGER}
     </update>

     <delete id="deleteById" parameterType="Integer" >
         delete from t_employee
         where id = #{id}
     </delete>

     <select id="findById"  parameterType="Integer" resultMap="employeeResultMap">
         select *
         from t_employee
         where id = #{id}
     </select>

     <select id="findAll" resultMap="employeeResultMap">
         select *
         from t_employee
     </select>

 </mapper>

5、Dao层接口

 package com.mcs.dao;

 import java.util.List;

 import com.mcs.entity.Employee;

 public interface EmployeeDao {

     public Employee add(Employee employee) throws Exception;
     public void edit(Employee employee) throws Exception;
     public void deleteById(Integer id) throws Exception;
     public Employee findById(Integer id) throws Exception;
     public List<Employee> findAll() throws Exception; 

 }

6、Dao层实现类

 package com.mcs.dao.impl;

 import java.util.ArrayList;
 import java.util.List;

 import org.apache.ibatis.session.SqlSession;

 import com.mcs.dao.EmployeeDao;
 import com.mcs.entity.Employee;
 import com.mcs.util.MybatisUtil;

 public class EmployeeDaoImpl implements EmployeeDao {

     public Employee add(Employee employee) throws Exception {
         SqlSession sqlSession = null;
         try {
             sqlSession = MybatisUtil.getSqlSession();
             sqlSession.insert("EmployeeMapper.add", employee);
             sqlSession.commit();
         } catch (Exception e) {
             e.printStackTrace();
             sqlSession.rollback();
             throw e;
         } finally {
             MybatisUtil.closeSqlSession();
         }
         return employee;
     }

     public void edit(Employee employee) throws Exception {
         SqlSession sqlSession = null;
         try {
             sqlSession = MybatisUtil.getSqlSession();
             sqlSession.insert("EmployeeMapper.updateById", employee);
             sqlSession.commit();
         } catch (Exception e) {
             e.printStackTrace();
             sqlSession.rollback();
             throw e;
         } finally {
             MybatisUtil.closeSqlSession();
         }
     }

     public void deleteById(Integer id) throws Exception {
         SqlSession sqlSession = null;
         try {
             sqlSession = MybatisUtil.getSqlSession();
             sqlSession.insert("EmployeeMapper.deleteById", id);
             sqlSession.commit();
         } catch (Exception e) {
             e.printStackTrace();
             sqlSession.rollback();
             throw e;
         } finally {
             MybatisUtil.closeSqlSession();
         }
     }

     public Employee findById(Integer id) throws Exception {
         SqlSession sqlSession = null;
         Employee employee = new Employee();
         try {
             sqlSession = MybatisUtil.getSqlSession();
             employee = sqlSession.selectOne("EmployeeMapper.findById", id);
         } catch (Exception e) {
             e.printStackTrace();
             throw e;
         } finally {
             MybatisUtil.closeSqlSession();
         }
         return employee;
     }

     public List<Employee> findAll() throws Exception {
         SqlSession sqlSession = null;
         List<Employee> employees = new ArrayList<Employee>();
         try {
             sqlSession = MybatisUtil.getSqlSession();
             employees = sqlSession.selectList("EmployeeMapper.findAll");
         } catch (Exception e) {
             e.printStackTrace();
             throw e;
         } finally {
             MybatisUtil.closeSqlSession();
         }
         return employees;
     }

 }

7、测试代码

 package com.mcs.test;

 import java.util.Date;
 import java.util.List;

 import org.apache.log4j.Logger;
 import org.junit.Before;
 import org.junit.Test;

 import com.mcs.dao.EmployeeDao;
 import com.mcs.dao.impl.EmployeeDaoImpl;
 import com.mcs.entity.Employee;

 public class TestEmployeeDao {
     /**
     * Logger for this class
     */
     private static final Logger logger = Logger.getLogger(TestEmployeeDao.class);

     private EmployeeDao employeeDao;

     @Before
     public void init() {
         employeeDao = new EmployeeDaoImpl();
     }

     @Test
     public void testFindById() throws Exception {
         Employee employee = employeeDao.findById();
         logger.debug(employee);
     }

     @Test
     public void testFindAll() throws Exception {
         List<Employee> employees = employeeDao.findAll();
         logger.debug(employees);
     }

     @Test
     public void testAdd() throws Exception {
         Employee employee = new Employee();
         employee.setName("赵小凤");
         employee.setSex("female");
         employee.setBirthday(new Date());
         employee.setEmail("xiaofeng@126.com");

         employee = employeeDao.add(employee);

         logger.debug(employee);
     }

     @Test
     public void testEditById() throws Exception {
         Employee employee = employeeDao.findById();
         employee.setDepartmentId();
         employee.setAddress("天津");

         employeeDao.edit(employee);

         logger.debug(employee);
     }

     @Test
     public void testDeleteById() throws Exception {
         Employee employee = employeeDao.findById();

         employeeDao.deleteById();

         logger.debug("已成功删除员工："  + employee.getName());
     }

 }