SSM搭建-Mybatis接口编程方式实现增删改查 （17）

    前面一章已经搭建好了eclipse,mybatis,mysql的环境，并且实现了一个简单的查询。请注意，这种方式是用SqlSession实例来直接执行已映射的SQL语句：

session.selectOne("com.mucfc.model.EmployeerMapper.findEmployeerByID", 1);

其实还有更简单的方法，而且是更好的方法，使用合理描述参数和SQL语句返回值的接口（比如EmployeerMapper.java），这样现在就可以至此那个更简单，更安全的代码，没有容易发生的字符串文字和转换的错误.下面是详细过程:

本文要改成以接口类来实现增删改查

整个工程目录 ：

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1、首先还是mybatis的配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"><!-- 这是根标签  --><configuration><!-- 元素允许在主配置文件之外提供一个properties格式对应文件，从而使得主配置文件更加通用。这样对部署非常有用  --> <properties resource="mysql.properties" /> <!-- 设置别名，一定要放在properties下面  --><typeAliases><typeAlias alias="Employeer" type="com.mucfc.model.Employeer"  /></typeAliases><!-- 配置数据源相关的信息  --><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://localhost:3306/test?characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="christmas258@"/>  --><property name="driver" value="${driver}" /><property name="url" value="${url}" /><property name="username" value="${username}" /><property name="password" value="${password}" /> </dataSource></environment></environments><!-- 列出映射文件 --><mappers><mapper resource="com/mucfc/model/Employeer.xml" /></mappers></configuration>

其中配置文件mysql.properties

driver=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/test?charset=utf8username=rootpassword=christmas258@

2、数据表对应的类Employeer.JAVA

package com.mucfc.model;import java.io.Serializable;/** * 雇员信息类 *@author linbingwen *@time 2015.5.11 */public class Employeer {private Integer employeer_id;private String employeer_name;private Integer employeer_age ;private String employeer_department;private String employeer_worktype;public Employeer() {super();}public Integer getEmployeer_id() {return employeer_id;}public void setEmployeer_id(Integer employeer_id) {this.employeer_id = employeer_id;}public String getEmployeer_name() {return employeer_name;}public void setEmployeer_name(String employeer_name) {this.employeer_name = employeer_name;}public Integer getEmployeer_age() {return employeer_age;}public void setEmployeer_age(Integer employeer_age) {this.employeer_age = employeer_age;}public String getEmployeer_department() {return employeer_department;}public void setEmployeer_department(String employeer_department) {this.employeer_department = employeer_department;}public String getEmployeer_worktype() {return employeer_worktype;}public void setEmployeer_worktype(String employeer_worktype) {this.employeer_worktype = employeer_worktype;}@Overridepublic String toString() {return "Employeer [employeer_id=" + employeer_id + ", employeer_name="+ employeer_name + ", employeer_age=" + employeer_age+ ", employeer_department=" + employeer_department+ ", employeer_worktype=" + employeer_worktype + "]";}}

然后是SQL语句的配置Employeer.xml：

<?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="com.mucfc.mapper.EmployeerMapper">      <!-- 查找 -->     <select id="findEmployeerByID" parameterType="int" resultType="Employeer">     select* from `t_employeer` where employeer_id =#{employeer_id}     </select>           <!-- 插入 -->        <!-- useGeneratedKeys设置为"true"表明要MyBatis获取由数据库自动生成的主键；keyProperty="id"指定把获取到的主键值注入到Employeer的id属性 -->     <insert id="addEmployeer" parameterType="Employeer"    useGeneratedKeys="true" keyProperty="employeer_id">          insert into `t_employeer`(employeer_name,employeer_age,employeer_department,employeer_worktype)         values(#{employeer_name},#{employeer_age},#{employeer_department},#{employeer_worktype})      </insert>           <!-- 删除  -->    <delete id="deleteEmployeer" parameterType="int">          delete from `t_employeer` where employeer_id = #{employeer_id}      </delete>          <!-- 修改 -->      <update id="updateEmployeer" parameterType="Employeer">          update t_employeer set employeer_name = #{employeer_name},employeer_age= #{employeer_age},employeer_department = #{employeer_department}        ,employeer_worktype=#{employeer_worktype}  where employeer_id = #{employeer_id}      </update>       </mapper>

注意com.mucfc.mapper.EmployeerMapper这个类是存在的，它是一个接口类，上一讲我们是使用com.mucfc.model.EmployeerMapper，而上一讲的这个类是不存在的

4、SQL语句映射类EmployeerMapper.java

package com.mucfc.mapper;import com.mucfc.model.Employeer;/** * SQL语句映射类 * @author linbingwen * @time 2015.5.11 */public interface EmployeerMapper {/** * 注意要和Employeer.xml的方法名对应 */public Employeer findEmployeerByID(int id);/** * 注意要和Employeer.xml的方法名对应 */public void addEmployeer(Employeer employeer);/** * 注意要和Employeer.xml的方法名对应 */public void deleteEmployeer(int id);/** * 注意要和Employeer.xml的方法名对应 */public void updateEmployeer(Employeer employeer);}

5、测试：

（1）增加命令

上一讲中的方式：

/** * 增加 */public static void addEmployeer(Employeer employeer){SqlSession session = null;try {session = sqlSessionFactory.openSession(); //返回值是记录条数              int resultCount = session.insert("com.mucfc.model.EmployeerMapper.addEmployeer", employeer );              System.out.printf("当前插入的employeer_id :%d    当前插入数据库中条数:%d " , employeer.getEmployeer_id() ,resultCount);  //获取插入对象的id              System.out.println("");            session.commit() ;  } finally {session.close();}}

改成以接口编程的方式：

/** * 增加 */public static void addEmployeer(Employeer employeer){SqlSession session = null;try {session = sqlSessionFactory.openSession();EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);employeerMapper.addEmployeer(employeer);            session.commit() ;  } finally {session.close();}}

（2）删除命令

上一讲中的方式：

/** * 删除 *  */public static void deleteEmployeer(int id){SqlSession session = null;try {session = sqlSessionFactory.openSession(); //返回值是记录条数   int resultCount=session.delete("com.mucfc.model.EmployeerMapper.deleteEmployeer",id);   System.out.println("当前删除数据库中条数: "+resultCount);  //获取插入对象的id              session.commit() ;  } finally {session.close();}}

改成以接口编程的方式：

/** * 删除 *  */public static void deleteEmployeer(int id){SqlSession session = null;try {session = sqlSessionFactory.openSession();EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);employeerMapper.deleteEmployeer(id);            session.commit() ;  } finally {session.close();}}

（3）查找命令

上一讲中的方式：

/** * 查找 */public static void findEmployeerById(int id) {SqlSession session = null;try {session = sqlSessionFactory.openSession();Employeer employeer = (Employeer) session.selectOne("com.mucfc.model.EmployeerMapper.findEmployeerByID", 1);if (employeer == null)System.out.println("null");elseSystem.out.println(employeer);} finally {session.close();}}

改成以接口编程的方式：

/** * 查找 */public static void findEmployeerById(int id) {SqlSession session = null;try {session = sqlSessionFactory.openSession();EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);Employeer employeer=employeerMapper.findEmployeerByID(id);if (employeer == null)System.out.println("null");elseSystem.out.println(employeer);} finally {session.close();}}

（4）修改命令

上一讲中的方式：

/** * 更改 */public static void updateEmployeer(Employeer employeer){SqlSession session = null;try {session = sqlSessionFactory.openSession();             session.update("com.mucfc.model.EmployeerMapper.updateEmployeer",employeer);                session.commit() ;  } finally {session.close();}}

改成以接口编程的方式：

/** * 更改 */public static void updateEmployeer(Employeer employeer){SqlSession session = null;try {session = sqlSessionFactory.openSession(); EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);employeerMapper.updateEmployeer(employeer);            session.commit() ;  } finally {session.close();}}

这是一个完整的测试：

package com.mucfc.test;import java.io.IOException;import java.io.Reader;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import com.mucfc.mapper.EmployeerMapper;import com.mucfc.model.Employeer;public class MybatisTest {private static SqlSessionFactory sqlSessionFactory;private static Reader reader;static {try {reader = Resources.getResourceAsReader("mybatis-config.xml");sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);} catch (Exception e) {e.printStackTrace();}}/** * 查找 */public static void findEmployeerById(int id) {SqlSession session = null;try {session = sqlSessionFactory.openSession();EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);Employeer employeer=employeerMapper.findEmployeerByID(id);if (employeer == null)System.out.println("null");elseSystem.out.println(employeer);} finally {session.close();}}/** * 增加 */public static void addEmployeer(Employeer employeer){SqlSession session = null;try {session = sqlSessionFactory.openSession();EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);employeerMapper.addEmployeer(employeer);            session.commit() ;  } finally {session.close();}}/** * 删除 *  */public static void deleteEmployeer(int id){SqlSession session = null;try {session = sqlSessionFactory.openSession();EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);employeerMapper.deleteEmployeer(id);            session.commit() ;  } finally {session.close();}}/** * 更改 */public static void updateEmployeer(Employeer employeer){SqlSession session = null;try {session = sqlSessionFactory.openSession(); EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);employeerMapper.updateEmployeer(employeer);            session.commit() ;  } finally {session.close();}}public static void main(String[] args) {Employeer employeer1=new Employeer();employeer1.setEmployeer_name("李四");employeer1.setEmployeer_age(23);employeer1.setEmployeer_department("产品一部");employeer1.setEmployeer_worktype("开发工程师");Employeer employeer2=new Employeer();employeer2.setEmployeer_name("张三");employeer2.setEmployeer_age(30);employeer2.setEmployeer_department("产品二部");employeer2.setEmployeer_worktype("测试工程师");Employeer employeer3=new Employeer();employeer3.setEmployeer_name("小王");employeer3.setEmployeer_age(22);employeer3.setEmployeer_department("产品三部");employeer3.setEmployeer_worktype("数据分析师");Employeer employeer4=new Employeer();employeer4.setEmployeer_name("明明");employeer4.setEmployeer_age(22);employeer4.setEmployeer_department("财会部");employeer4.setEmployeer_worktype("财务人员");//插入     addEmployeer(employeer1);     addEmployeer(employeer2);     addEmployeer(employeer3);     addEmployeer(employeer4);     findEmployeerById(26);     deleteEmployeer(27);//更改employeer2.setEmployeer_id(28);employeer2.setEmployeer_age(21);employeer2.setEmployeer_department("产品四部");updateEmployeer(employeer2);}}

测试结果：

插入了4条数据，ID为25~28

然后27号被删除

29号被修改

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