2.MyBatis有代理增删改

2.1 创建一个javaweb项目MyBatis_Part1，并创建如下sql脚本

create user holly identified by sys;
grant dba to holly;
conn holly/sys
create table teacher(id number primary key,tname varchar2(20),pwd varchar2(20));
create sequence seq_teacher;
insert into teacher values(seq_teacher.nextval,'holly','123');
insert into teacher values(seq_teacher.nextval,'石头','123');
insert into teacher values(seq_teacher.nextval,'朱亚楠','123');
insert into teacher values(seq_teacher.nextval,'陈明','123');
commit;

2.2 在项目的src下创建Configuration.xml主配置文

<?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>
   <!-- 路径别名配置 -->
   <typeAliases>
     <typeAlias type="com.entity.Dept" alias="Dept"/>
   </typeAliases>
   
   <!-- 链接数据库的环境配置，development开发模式 -->
   <environments default="development">
      <environment id="development">
        <!-- jdbc管理事务 -->
        <transactionManager type="jdbc"/>
        <!-- 数据源配置 -->
        <dataSource type="POOLED">
           <property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
           <property name="url" value="jdbc:oracle:thin:@127.0.0.1:1521:orcl"/>
           <property name="username" value="scott"/>
           <property name="password" value="tiger"/>
        </dataSource>
        
      </environment>
   </environments>
   <!-- 注册映射文件 -->
   <mappers>
     <mapper resource="com/mapper/DeptMapper.xml"/>
   </mappers>

   
 
</configuration>

2.3 在src下的com.entity包下创建Teacher.java实体类

package com.entity;

public class Teacher {
    private int id;
    private String tname;
    private String pwd;
    public Teacher() {
    }
    
    public Teacher(String tname, String pwd) {
        this.tname = tname;
        this.pwd = pwd;
    }

    public Teacher(int id, String tname, String pwd) {
        this.id = id;
        this.tname = tname;
        this.pwd = pwd;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getTname() {
        return tname;
    }

    public void setTname(String tname) {
        this.tname = tname;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "Teacher [id=" + id + ", pwd=" + pwd + ", tname=" + tname + "]";
    }
}

2.4 在src下的com.mapper包下创建TeacherMapper.java映射接口

package com.mapper;

import java.util.List;

import com.entity.Teacher;

public interface TeacherMapper {
    //1.查所有
    List<Teacher> findAll();
    //2.根据id查询
    Teacher findById(int id);
    //3.添加
    int saveTeacher(Teacher teacher);
    //4.修改
    int updateTeacher(Teacher teacher);
    //5.删除
    int deleteTeacher(int id);
    

}

2.5在src下的com.mapper包下创建TeacherMapper.xml映射配置文件

<?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" >
<!-- 如果是有代理，则namespace的值必须是映射接口的全路径 -->
<mapper namespace="com.mapper.TeacherMapper">
  <!-- 1.查询所有 -->
  <select id="findAll" resultType="Teacher">
    select * from teacher
  </select>
  
  <!-- 2.根据id查询所有 -->
  <select id="findById" resultType="Teacher" parameterType="int">
    select * from teacher where id=#{id}
  </select>
  
  <!-- 3.添加 -->
  <insert id="saveTeacher" parameterType="Teacher">
    insert into teacher values(seq_teacher.nextval,#{tname},#{pwd})
  </insert>
  
  <!-- 4.修改 -->
  <update id="updateTeacher" parameterType="Teacher">
    update teacher set tname=#{tname},pwd=#{pwd}
  </update>
  
  <!-- 5.删除 -->
  <delete id="deleteTeacher" parameterType="int">
    delete from teacher where id=#{id}
  </delete>
</mapper>

2.6在src下的com.mapper.impl包下创建TeacherMapperImpl.java映射实现类文件

package com.mapper.impl;

import java.util.List;

import org.apache.ibatis.session.SqlSession;

import com.entity.Teacher;
import com.mapper.TeacherMapper;
import com.util.MyBatisUtil;

public class TeacherMapperImpl implements TeacherMapper {
    /**
     *1.查询所有
     *     */
    public List<Teacher> findAll() {
        SqlSession sqlsession=MyBatisUtil.getSqlSession(false);
        //利用反射产生代理对象（动态代理）
        TeacherMapper mapper=sqlsession.getMapper(TeacherMapper.class);
        try {
            List<Teacher> list=mapper.findAll();
            sqlsession.close();
            return list;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        
    }
    /**
     * 2.查询单条
     */
    public Teacher findById(int id) {
        SqlSession sqlsession=MyBatisUtil.getSqlSession(false);
        TeacherMapper mapper=sqlsession.getMapper(TeacherMapper.class);
        Teacher teacher=null;
        try {
            teacher = mapper.findById(id);
            sqlsession.close();
            return teacher;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    /**
     * 添加
     */
    public int saveTeacher(Teacher teacher) {
        SqlSession sqlsession=MyBatisUtil.getSqlSession(true);
        TeacherMapper mapper=sqlsession.getMapper(TeacherMapper.class);
        try {
            int num=mapper.saveTeacher(teacher);
            sqlsession.close();
            return num;
        } catch (Exception e) {
            e.printStackTrace();
            
            return 0;
        }
    }
   /**
    * 4.修改
    */
    public int updateTeacher(Teacher teacher) {
        SqlSession sqlsession=MyBatisUtil.getSqlSession(false);
        TeacherMapper mapper=sqlsession.getMapper(TeacherMapper.class);
        try {
            int num=mapper.updateTeacher(teacher);
            sqlsession.close();
            return num;
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }
    /**
     * 5.根据id删除
     */
    public int deleteTeacher(int id) {
        SqlSession sqlsession=MyBatisUtil.getSqlSession(false);
        TeacherMapper mapper=sqlsession.getMapper(TeacherMapper.class);
        try {
            int num=mapper.deleteTeacher(id);
            sqlsession.close();
            return num;
        } catch (Exception e) {
            e.printStackTrace();
            return 0;
        }
    }

}