mybatis，初级入门

朴灿烈づ我的快乐病毒、 2022-06-09 07:13 153阅读 0赞

首先感谢：[渐行渐远....那些错过的青春][....]：http://www.cnblogs.com/liangxiaofeng/p/6371866.html

我的第一个mybatis项目，以前总是对mybatis有畏惧感，现在自己调试成功了一个，让mybatis从圣坛上降下来了。也让其他兄弟们尝尝鲜。

先来个项目目录图：

![Center][]

不讲mybatis原理，因为通过测试后，再去理解原理就很清楚了。最主要是，不能打断大家复制代码不是嘛，哈哈哈！

**UserBean.java**

package com.fei.mybatis.beans;
    
    import java.io.Serializable;
    
    public class UserBean implements Serializable {
    
    	private static final long serialVersionUID = 1L;
    	private Integer id;
    	private String username;
    	private String password;
    	private Double account;
    	
    	public UserBean(){
    		
    	}
    	
    	public UserBean(String username,String password,Double account){
    		super();
    		this.username = username;
    		this.password = password;
    		this.account = account;
    		
    	}
    	
    	public UserBean(Integer id,String username,String password,Double account){
    		super();
    		this.id = id;
    		this.username = username;
    		this.password = password;
    		this.account = account;
    	}
    
    	public Integer getId() {
    		return id;
    	}
    
    	public void setId(Integer id) {
    		this.id = id;
    	}
    
    	public String getUsername() {
    		return username;
    	}
    
    	public void setUsername(String username) {
    		this.username = username;
    	}
    
    	public String getPassword() {
    		return password;
    	}
    
    	public void setPassword(String password) {
    		this.password = password;
    	}
    
    	public Double getAccount() {
    		return account;
    	}
    
    	public void setAccount(Double account) {
    		this.account = account;
    	}
    	
    	@Override
    	public String toString() {
    		
    		return "UserBean ,id="+id+",username="+username+",password="+password+
    				",account="+account;
    	}
    	
    	
    }

UserMapper.java

package com.fei.mybatis.mapper;
    
    import java.util.List;
    
    import com.fei.mybatis.beans.UserBean;
    
    public interface UserMapper {
    	
    	//新增用户
    	public int insertUser(UserBean user) throws Exception;
    	
    	//修改用户
    	public int updateUser(UserBean user,int id) throws Exception;
    	
    	//删除用户
    	public int deleteUser(int id) throws Exception;
    	
    	//根据id查询用户信息
    	public UserBean selectUserById(int id) throws Exception;
    	
    	//查询所有用户的信息
    	public List<UserBean> selectAllUser() throws Exception;
    	
    	
    }

UserMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.fei.mybatis.mapper.UserMapper">
    
       <resultMap id="userMap" type="UserBean">
            <id property="id" column="id" javaType="java.lang.Integer"></id>
            <result property="username" column="username" javaType="java.lang.String"></result>
            <result property="password" column="password" javaType="java.lang.String"></result>
            <result property="account" column="account" javaType="java.lang.Double"></result>
        </resultMap>
        
        
    
    
    
    
        <insert id="insertUser" useGeneratedKeys="true" keyProperty="id">
            insert into t_user (username,password,account) values (#{username},#{password},#{account})
        </insert>
        
        <update id="updateUser" >
          update t_user set username=#{username},password=#{password},account=#{account} where id=#{id}
        </update>
        
        <delete id="deleteUser" parameterType="int">
         delete from t_user where id=#{id}  
        </delete>
        
        <select id="selectUserById" parameterType="int" resultMap="userMap">
         select * from t_user where id=#{id}
        </select>
        
        <select id="selectAllUser" resultMap="userMap">
         select * from t_user
        </select>
        
        
    </mapper>

UserService.java

package com.fei.mybatis.service;
    
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    
    import com.fei.mybatis.beans.UserBean;
    import com.fei.mybatis.mapper.UserMapper;
    import com.fei.mybatis.tools.DBTools;
    
    public class UserService {
    	static DBTools tool = new DBTools();
    	
    	public static void main(String[] args) {
    		insertUser();
    //		deleteUser();
    //		selectUserById();
    //		selectAllUser();
    	}
    	
    	/**
    	 * 新增用户
    	 */
    	private static void insertUser(){
    		
    		SqlSession session = tool.getSession();
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		UserBean user = new UserBean("tom","110",2222.0); 
    		try {
    			mapper.insertUser(user);
    			System.out.println(user.toString());
    			session.commit();
    		} catch (Exception e) {
    
    			e.printStackTrace();
    			session.rollback();
    		}
    	}
    	
    	/**
    	 *  删除用户
    	 */
    	private static void deleteUser(){
    		SqlSession session = tool.getSession();
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		try {
    			mapper.deleteUser(1);
    			session.commit();
    		} catch (Exception e) {
    			e.printStackTrace();
    			session.rollback();
    		}
    	}
    	
    	/**
    	 * 根据id查询用户
    	 */
    	private static void selectUserById(){
    		SqlSession session = tool.getSession();
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		try {
    			UserBean user = mapper.selectUserById(2);
    			System.out.println(user.toString());
    			session.commit();
    		} catch (Exception e) {
    			// TODO: handle exception
    			e.printStackTrace();
    			session.rollback();
    		}
    	}
    	
    	/**
    	 * 查询所有的用户
    	 */
    	private static void selectAllUser(){
    		SqlSession session = tool.getSession();
    		UserMapper mapper = session.getMapper(UserMapper.class);
    		try {
    			List<UserBean> user = mapper.selectAllUser();
    			System.out.println(user.toString());
    			session.commit();
    		} catch (Exception e) {
    			e.printStackTrace();
    			session.rollback();
    		}
    	}
    	
    
    }

DBTools.java

package com.fei.mybatis.tools;
    
    import java.io.Reader;
    import java.sql.Connection;
    
    import javax.annotation.Resource;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.Configuration;
    import org.apache.ibatis.session.ExecutorType;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.apache.ibatis.session.TransactionIsolationLevel;
    
    public class DBTools {
    	
    	public static SqlSessionFactory sessionFactory = new SqlSessionFactory() {
    		
    		@Override
    		public SqlSession openSession(ExecutorType arg0, Connection arg1) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession(ExecutorType arg0, TransactionIsolationLevel arg1) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession(ExecutorType arg0, boolean arg1) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession(ExecutorType arg0) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession(TransactionIsolationLevel arg0) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession(Connection arg0) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession(boolean arg0) {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public SqlSession openSession() {
    			// TODO Auto-generated method stub
    			return null;
    		}
    		
    		@Override
    		public Configuration getConfiguration() {
    			// TODO Auto-generated method stub
    			return null;
    		}
    	};
    	
    	static{
    		try {
    			//使用Mybatis提供的Resource类加载mybatis的配置文件
    			Reader reader = Resources.getResourceAsReader("mybatis.cfg.xml");
    			//构建sqlSession的工厂
    			sessionFactory = new SqlSessionFactoryBuilder().build(reader);
    		} catch (Exception e) {
    			
    		}
    	}
    	
    	//创建能执行映射文件中的sqlSession
    	public static SqlSession getSession(){
    		return sessionFactory.openSession();
    	}
    	
    }

log4j.properties

是空的

mybatis.cfg.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>
    
      
      <properties resource="mysql.properties"></properties>
      
      
       
       <typeAliases >
            
            
            <package name="com.fei.mybatis.beans"/>
       </typeAliases>
       
       
       
         <environments default="cybatis">
            <environment id="cybatis">
                
                <transactionManager type="JDBC" />
                
                
                
                
                
                <dataSource type="POOLED">
                    <property name="driver" value="${jdbc.driver}" />
                    <property name="url" value="${jdbc.url}" />
                    <property name="username" value="${jdbc.username}" />
                    <property name="password" value="${jdbc.password}" />
                </dataSource>
            </environment>
        </environments> 
        
        
        <mappers>
            
            
            <package name="com/fei/mybatis/mapper"/>
        </mappers>
    </configuration>

mysql.properties

jdbc.driver=com.microsoft.sqlserver.jdbc.SQLServerDriver
    jdbc.url=jdbc:sqlserver://localhost:1433;DatabaseName=mybatis
    jdbc.username=sa
    jdbc.password=写自己的密码

这样就完工了，运行UserService.java,run  as ，run application，就可以看到结果：

![Center 1][]

！！！！！！！！！！！！！！！！！！！！！！！！完工了！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！

[....]: http://www.cnblogs.com/liangxiaofeng/
[Center]: /images/20220609/5bf22a3b3066433e8dad1a96eae77b55.png
[Center 1]: /images/20220609/36c469e173854f769ca6fb96c5505df1.png