前面一章Mybatis入门概述及第一个Mybatis实例实现增删改查 ，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：
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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 ：
本文示例工程免费下载
1、首先还是mybatis的配置文件mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
br>PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<!-- 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>
其中配置文件mysql.properties
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test?charset=utf8
username=root
password=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;
}
@Override
public 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" ?>
br>"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 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>
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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Mybatis入门概述及第一个Mybatis实例实现增删改查 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【Mybatis】Mybatis入门概述及第一个Mybatis实例实现增删改查 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【Mybatis】Mybatis入门概述及第一个Mybatis实例实现增删改查 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");
else
System.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");
else
System.out.println(employeer);
} finally {
session.close();
}
}
（4）修改命令
上一讲【Mybatis】Mybatis入门概述及第一个Mybatis实例实现增删改查 中的
/**
- 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");
else
System.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
