mybatis学习，简单实例

快来打我* 2022-05-29 03:06 291阅读 0赞

因为工作中所使用的开发框架都是ssh，很长时间没有使用ssh框架之外的框架，最近温习了一下mybatis，废话不多说，直接上实例。

### 1、首先建立java web项目    ###

![Image 1][]

### 2、导入开发所需jar包，jar包可以去mybatis官网下载，[mybatis官网jar包下载步骤][mybatis_jar]    ###

![Image 1][]

### 3、创建测试表，下面是我的表结构。    ###

![Image 1][]

### 4、创建配置文件    ###

![Image 1][]

#### jdbc配置文件：    ####

##mysql
    jdbc.driverClassName=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://localhost:3306/world?useOldAliasMetadataBehavior=true&allowMultiQueries=true
    jdbc.username=root
    jdbc.password=mlnsoft

#### mybatis配置文件： ####

### 5、创建Javabean，接口文件和映射xml文件    ###

![Image 1][]

#### City.java    ####

package com.cp.myproject.bean;
    
    import java.io.Serializable;
    
    public class City implements Serializable{
    
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	private Integer id;
    	private String name;
    	private String countryCode;
    	private String district;
    	private Integer population;
    	/**
    	 * @return the id
    	 */
    	public Integer getId() {
    		return id;
    	}
    	/**
    	 * @param id the id to set
    	 */
    	public void setId(Integer id) {
    		this.id = id;
    	}
    	/**
    	 * @return the name
    	 */
    	public String getName() {
    		return name;
    	}
    	/**
    	 * @param name the name to set
    	 */
    	public void setName(String name) {
    		this.name = name;
    	}
    	/**
    	 * @return the countryCode
    	 */
    	public String getCountryCode() {
    		return countryCode;
    	}
    	/**
    	 * @param countryCode the countryCode to set
    	 */
    	public void setCountryCode(String countryCode) {
    		this.countryCode = countryCode;
    	}
    	
    	/**
    	 * @return the population
    	 */
    	public Integer getPopulation() {
    		return population;
    	}
    	/**
    	 * @param population the population to set
    	 */
    	public void setPopulation(Integer population) {
    		this.population = population;
    	}
    	/* (non-Javadoc)
    	 * @see java.lang.Object#toString()
    	 */
    	@Override
    	public String toString() {
    		return "City [id=" + id + ", name=" + name + ", countryCode="
    				+ countryCode + ", distinct=" + district + ", population="
    				+ population + "]";
    	}
    	/**
    	 * @return the district
    	 */
    	public String getDistrict() {
    		return district;
    	}
    	/**
    	 * @param district the district to set
    	 */
    	public void setDistrict(String district) {
    		this.district = district;
    	}
    	
    	
    }

#### CityMapper.java ####

package com.cp.myproject.mapper;
    
    import java.util.List;
    
    import com.cp.myproject.bean.City;
    
    public interface CityMapper {
    
    	/**
    	 * 增加
    	 * @param city
    	 * @return
    	 */
    	public int insert(City city);
    	/**
    	 * 删除
    	 * @param id
    	 * @return
    	 */
    	public int delete (int id);
    	/**
    	 * 更新
    	 * @param city
    	 * @param id
    	 * @return
    	 */
    	public int update (City city);
    	/**
    	 * 根据id查询
    	 * @param id
    	 * @return
    	 */
    	public City selectById(int id);
    	/**
    	 * 查询所有的记录
    	 * @return
    	 */
    	public List<City> findAll();
    	/**
    	 * 更新或插入
    	 * @param city
    	 * @return
    	 */
    //	public int saveOrUpdate(City city);
    }

#### CityMapper.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.cp.myproject.mapper.CityMapper">
    
       <resultMap id="cityMap" type="City">
            <id property="id" column="ID" javaType="java.lang.Integer"></id>
            <result property="name" column="Name"></result>
            <result property="countryCode" column="CountryCode" ></result>
            <result property="district" column="District" ></result>
            <result property="population" column="Population" javaType="java.lang.Integer"></result>
        </resultMap>
        
        
    
    
    
    
        <insert id="insert" useGeneratedKeys="true" keyProperty="id">
            insert into city (name,countryCode,district) values (#{name},#{countryCode},#{district})
        </insert>
        
        <update id="update" parameterType="com.cp.myproject.bean.City" >
          update city
          <set>
          <if test="district != null">district=#{district},</if>
          <if test="name != null">name=#{name},</if>
          <if test="countryCode != null">countryCode=#{countryCode},</if>
          <if test="population != null">population=#{population}</if>
        </set>
           where id = #{id}
        </update>
        
        <delete id="delete" parameterType="int">
         delete from city where id=#{id}  
        </delete>
        
        <select id="selectById" parameterType="int" resultMap="cityMap">
         select * from city where id=#{id}
        </select>
        
        <select id="findAll" resultMap="cityMap">
         select * from city
        </select>
        
        
    </mapper>

### 6、将mapper xml文件 在mybatis.xml 中注册。    ###

<?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="jdbc.properties"></properties>
       
       <typeAliases >
            
            
            <package name="com.cp.myproject.bean"/>
       </typeAliases>
       
         <environments default="cybatis">
            <environment id="cybatis">
                
                <transactionManager type="JDBC" />
                
                
                
                
                
                <dataSource type="POOLED">
                    <property name="driver" value="${jdbc.driverClassName}" />
                    <property name="url" value="${jdbc.url}" />
                    <property name="username" value="${jdbc.username}" />
                    <property name="password" value="${jdbc.password}" />
                </dataSource>
            </environment>
        </environments> 
        
        <mappers>
            
            
            <package name="com/cp/myproject/mapper"/>
        </mappers>
    </configuration>

### 7、工具类创建 ###

![Image 1][]

package com.cp.myproject.DbTools;
    
    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;
    
    public class DbTools {
    	
    	 public static SqlSessionFactory sessionFactory;
    	    
    	    static{
    	        try {
    	            //使用MyBatis提供的Resources类加载mybatis的配置文件
    	            Reader reader = Resources.getResourceAsReader("mybatis.xml");
    	            //构建sqlSession的工厂
    	            sessionFactory = new SqlSessionFactoryBuilder().build(reader);
    	        } catch (Exception e) {
    	            e.printStackTrace();
    	        }
    	        
    	    }
    	    //创建能执行映射文件中sql的sqlSession
    	    public static SqlSession getSession(){
    	        return sessionFactory.openSession();
    	    }
    
    }

8、创建测试类 CityService.java

package com.cp.myproject.service;
    
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    
    import com.cp.myproject.DbTools.DbTools;
    import com.cp.myproject.bean.City;
    import com.cp.myproject.mapper.CityMapper;
    
    public class CityService {
    	/**
    	 * 查询所有的记录
    	 */
    	private static void findAll(){
    		SqlSession session=DbTools.getSession();
            CityMapper mapper=session.getMapper(CityMapper.class);
            try {
            List<City> user=mapper.findAll();
            for(City citys:user){
            	System.out.println("name: "+citys.getName()+", district: "+citys.getDistrict()+", population: "+citys.getPopulation()+", countrycode: "+citys.getCountryCode());
            }
            //System.out.println(user.toString());
            session.commit();
            } catch (Exception e) {
                e.printStackTrace();
                session.rollback();
            }
    	}
    	
    	/**
    	 * 根据id查询记录
    	 */
    	private static void findbyid(){
    		SqlSession session=DbTools.getSession();
            CityMapper mapper=session.getMapper(CityMapper.class);
            try {
    			City city = mapper.selectById(1);
    			System.out.println("name: "+city.getName()+", district: "+city.getDistrict());
    		} catch (Exception e) {
    			e.printStackTrace();
                session.rollback();
    		}
    	}
    	/**
    	 * 增加记录
    	 */
    	private static void insert(){
    		SqlSession session=DbTools.getSession();
            CityMapper mapper=session.getMapper(CityMapper.class);
            try {
    			City city = new City();
    			city.setName("aaa");
    			city.setCountryCode("aaa");
    			city.setDistrict("aaa");
    			mapper.insert(city);
    		} catch (Exception e) {
    			e.printStackTrace();
                            session.rollback();
    		}
    	}
    	
    	/**
    	 * 记录更新
    	 */
    	public static void update(){
    		SqlSession session=DbTools.getSession();
            CityMapper mapper=session.getMapper(CityMapper.class);
            try {
            	City city = mapper.selectById(4081);
            	city.setDistrict("88888");
            	mapper.update(city);
    		} catch (Exception e) {
    			e.printStackTrace();
                session.rollback();
    		}
    	}
    	/**
    	 * 删除记录
    	 */
    	public static void delete(){
    		SqlSession session=DbTools.getSession();
            CityMapper mapper=session.getMapper(CityMapper.class);
            try {
    			mapper.delete(4080);
    		} catch (Exception e) {
    			e.printStackTrace();
                session.rollback();
    		}
    	}
    	
    	
    	public static void main(String[] args) {
    //		saveOrUpdate();
    //		delete();
    //		findAll();
    		findbyid();
    //		insert();
    //		update();
    	}
    
    }

### 9、运行测试类 CityService.java ###

Run As---->Java Appliation

### 10、运行结果    ###

![Image 1][]

### 项目源码：[mybatis实例源码下载][mybatis]    ###

本文参考博文：[http://www.cnblogs.com/hellokitty1/p/5216025.html][http_www.cnblogs.com_hellokitty1_p_5216025.html]

[Image 1]: 
[mybatis_jar]: https://jingyan.baidu.com/article/19020a0a773e5c529d284200.html
[mybatis]: https://download.csdn.net/download/chenping1993/10289022
[http_www.cnblogs.com_hellokitty1_p_5216025.html]: http://www.cnblogs.com/hellokitty1/p/5216025.html