<?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>
  <properties resource="Config.properties"/>
  <typeAliases>
    <package name="com.model"/>
  </typeAliases>
  <environments default="development">

    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
      </dataSource>
    </environment>
    <!--第二个环境-->
    <environment id="publish">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED"/>
    </environment>
  </environments>
</configuration>

<!DOCTYPE configuration
    PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-config.dtd">

driver = com.mysql.jdbc.Driver 
url=jdbc:mysql://localhost:3306/shop 
username=root 
password=123456

<?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>
  <select id="load" parameterType="int" resultType="User">
    SELECT * from user WHERE id=#{id}
  </select>
</mapper>

<mappers>
  <mapper resource="com/model/User.xml"/>
</mappers>

public static void main(String[] args) {
    try {
      InputStream is = Resources.getResourceAsStream("Config.xml");//读取配置文件
      SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);//利用配置文件创建factory
      SqlSession session = factory.openSession();//获取session
      User user = session.selectOne(User.class.getName()+".load",1);//调用load函数
      System.out.println(user.getNickname());//输出昵称
      session.close();//关闭session
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

package com.util;

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 java.io.IOException;
import java.io.InputStream;

/**
 * Created by nl101 on 2016/2/23.
 */
public class SessionUtil {
  private static SqlSessionFactory factory= null;
  static {
    try {
      InputStream is = Resources.getResourceAsStream("Config.xml");//读取配置文件
      factory = new SqlSessionFactoryBuilder().build(is);//利用配置文件创建factory
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
   * 获取session
   * @return
   */
  public static SqlSession getSession(){
    return factory.openSession();
  }

  /**
   * 关闭session
   * @param session
   */
  public static void closeSession(SqlSession session){
    if (session!=null) session.close(); session = null;
  }
}

 <!--增加一个用户-->
  <insert id="add" parameterType="User">
    INSERT INTO user VALUES 
    (null,#{username},#{password},#{nickname},#{type})
  </insert>

/**
   /**
   * 添加一个用户
   * @param user 要添加的用户
   * @return true成功
   */
  public boolean add(User user){
    int isAdd = 0;
    SqlSession session = SessionUtil.getSession();
    try {
      isAdd = session.insert(User.class.getName()+".add",user);
      session.commit();//提交
    } catch (Exception e) {
      session.rollback();//提交失败则回滚

    }finally {
      SessionUtil.closeSession(session);
    }
    System.out.println(isAdd);
    return isAdd>0;
  }


public boolean delete(int id)删除一个用户

 <!--删除一个用户-->
  <delete id="delete" parameterType="int">
    DELETE FROM user WHERE id=#{id}
  </delete>

/**
   *根据id删除用户
   * @param id 要删除用户的id
   * @return true成功
   */
   public boolean delete(int id){
    int isDelete = 0;
    SqlSession session = SessionUtil.getSession();
    try {
      isDelete = session.delete(User.class.getName()+".delete",id);
      session.commit();
    } catch (Exception e) {
      session.rollback();//失败返回
      System.out.println("删除用户失败");
      e.printStackTrace();
    }finally {
      SessionUtil.closeSession(session);
    }
    return isDelete>0;
  }

public boolean update(User user)更新用户

<!--修改一个用户-->
  <update id="update" parameterType="User" >
    UPDATE user SET username=#{username},password=#{password},nickname=#{nickname},type=#{type} where id=#{id}
  </update>

/**
   *更新用户
   * @param user 要更新的用户
   * @return true成功
   */
   public boolean update(User user){
    int isUpdate = 0;
    SqlSession session = SessionUtil.getSession();
    try {
      isUpdate = session.delete(User.class.getName()+".update",user);
      session.commit();
    } catch (Exception e) {
      session.rollback();//失败返回
      System.out.println("更新用户失败");
      e.printStackTrace();
    }finally {
      SessionUtil.closeSession(session);
    }
    return isUpdate>0;
  }


public User login(String username, String password)判断用户是否存在

<!--用户登录判断-->
  <select id="login" parameterType="String" resultType="User">
    SELECT * FROM user WHERE username=#{username}
  </select>

/**
   * 判断一个用户是否存在
   * @param username 用户名
   * @param password 密码
   * @return 存在返回User 不存在返回null
   */
  public User login(String username, String password){
    User user = null;
    SqlSession session = SessionUtil.getSession();
    try {
      user = session.selectOne(SOAPBinding.Use.class.getName()+".login",username);
      //当密码不对的时候置user为null
      if (!user.getPassword().equals(password)){
        user = null;
      }

    } finally {
      SessionUtil.closeSession(session);
    }
    return user;
  }

public Pager find(String name,String sort,String order)分页处理

 <!--分页代码-->
  <select id="find" parameterType="Map" resultType="User">
    SELECT * from user
    <if test="name!=null">WHERE (username LIKE #{name} or nickname LIKE #{name})</if>
     ORDER BY ${sort} ${order}
      LIMIT #{pageStart},#{pageSize}
  </select>
  <!--分页总记录数-->
  <select id="findcount" parameterType="Map" resultType="int">
    SELECT count(*) from user
    <if test="name!=null">WHERE (username LIKE #{name} or nickname LIKE #{name})</if>
  </select>

/**
   * 根据指定条件分页查询
   * @param name 查询条件,null代表无条件
   * @param sort 排序条件,null代表按照id排序
   * @param order 排序条件,null代表升序
   * @return
   */
  public Pager<User> find(String name,String sort,String order){
    int pageStart = SystemContext.getPageStart();//分页起始
    int pageSize = SystemContext.getPageSize();//分页大小
    Pager<User> pagers = new Pager<>();
    Map<String,Object> maps = new HashMap<>();
    if (name!=null && !name.equals("")){
      name = "%"+name+"%";
      maps.put("name",name);
    }
    if (sort==null || sort.equals("")){
      sort = "id";//默认按照id排序
    }
    if (order==null || order.equals("")){
      order = "asc";//默认排序
    }
    maps.put("sort",sort);
    maps.put("order",order);
    maps.put("pageStart",pageStart);
    maps.put("pageSize",pageSize);
    SqlSession session = SessionUtil.getSession();
    List<User> datas = null;
    try {
      datas = session.selectList(User.class.getName()+".find",maps);//获取记录
      pagers.setDatas(datas);
      pagers.setPageSize(pageSize);
      pagers.setPageStart(pageStart);
      int totalRecord = session.selectOne(User.class.getName()+".findcount",maps);//获取记录总数
      pagers.setTotalRecord(totalRecord);
      pagers.setPageIndex(pageStart/pageSize+1);

    } finally {
      SessionUtil.closeSession(session);
    }

    return pagers;
  }