开发过程中使用MyBatis的大概思路：

ゝ一纸荒年。 2022-05-18 02:36 244阅读 0赞

1：设计好数据表。

2：写Mybaits的配置文件

3：编写与数据表对应的持久化类。

4：编写mapper。如果采用XML的方式，需要为持久化类编写mapper配置文件。如果采用注解方式，为持久化类编写相应的Mapper类。

5：写一个MyBatis的工具类，用来创建SqlSession

6：最好创建service类，为每个持久化类进行操作的封装。

7：然后就调用封装好的service进行操作。

config.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="jdbc.properties"></properties>
    
        
        <environments default="development">
    
            
            <environment id="development">
                
                <transactionManager type="JDBC"></transactionManager>
                
                <dataSource type="POOLED">
                    <property name="driver" value="${driver}"></property>
                    <property name="url" value="${url}"></property>
                    <property name="username" value="${username}"></property>
                    <property name="password" value="${password}"></property>
    
                </dataSource>
            </environment>
        </environments>
    
        <mappers>
            
            <package name="com.imooc.cake.mapper"></package>
        </mappers>
    
    </configuration>

Mybatis工具类:MyBatisUtils

package com.imooc.cake.common;
    
    
    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.Reader;
    
    /**
     * MyBatis的工具类
     */
    public class MyBatisUtils {
    
        private static SqlSessionFactory sqlSessionFactory;
        private static Reader reader;
    
        static{
            String resource = "config.xml";
            try {
                //创建配置文件的输入流
                reader = Resources.getResourceAsReader(resource);
                //创建SqlSessionFactory,也就是数据库会话的工厂类
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        //创建会话
        public static SqlSession openSession(){
            return sqlSessionFactory.openSession();
        }
    }

持久化类：Cake

package com.imooc.cake.entity;
    
    import java.util.Date;
    
    public class Cake {
    
        private Long id;
        private Long categoryId;
        private String name;
        private Integer level;
        private Integer price;
        private byte[] smallImg;
    
        private Date createTime;
        private Date updateTime;
    
        public Long getId() {
            return id;
        }
    
        public void setId(Long id) {
            this.id = id;
        }
    
        public Long getCategoryId() {
            return categoryId;
        }
    
        public void setCategoryId(Long categoryId) {
            this.categoryId = categoryId;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getLevel() {
            return level;
        }
    
        public void setLevel(Integer level) {
            this.level = level;
        }
    
        public Integer getPrice() {
            return price;
        }
    
        public void setPrice(Integer price) {
            this.price = price;
        }
    
        public byte[] getSmallImg() {
            return smallImg;
        }
    
        public void setSmallImg(byte[] smallImg) {
            this.smallImg = smallImg;
        }
    
        public Date getCreateTime() {
            return createTime;
        }
    
        public void setCreateTime(Date createTime) {
            this.createTime = createTime;
        }
    
        public Date getUpdateTime() {
            return updateTime;
        }
    
        public void setUpdateTime(Date updateTime) {
            this.updateTime = updateTime;
        }
    }

持久化类对应的Mapper类：CakeMapper

package com.imooc.cake.mapper;
    
    
    import com.imooc.cake.entity.Cake;
    import org.apache.ibatis.annotations.*;
    
    import java.util.List;
    
    public interface CakeMapper {
    
    
        @Select("select * from cake order by create_time desc limit #{sikp},#{size}")
        @Results({
                @Result(id=true,column="id",property="id"),
                @Result(column = "category_id",property="categoryId"),
                @Result(column = "name",property="name"),
                @Result(column = "level",property="level"),
                @Result(column = "price",property="price"),
                @Result(column = "create_time",property="createTime"),
                @Result(column = "update_time",property="updateTime"),
        })
        List<Cake> getCakes(Integer skip, Integer size);
    
        @Select("select id, category_id,name,level,price,create_time createTime,update_time updateTime from" +
                " cake where category_id=#{categoryId} order by create_time desc limit #{sikp},#{size}")
        List<Cake> getCakesByCategoryId(@Param("categoryId")Long categoryId, @Param("skip")Integer skip, @Param("size")Integer size);
    
        @Select("select count(*) from cake where category_id = #{categoryId}")
        int countCakesByCategoryId(@Param("categoryId")Long categoryId);
    
        @Insert("insert into cake(category_id,name,level,price,small_img,create_time,update_time) " +
                "value(#{cake.categoryId},#{cake.name},#{cake.level},#{cake.price},#{cake.smallImg},#{cake.createTime},#{cake.updateTime})")
        void addCake(Cake cake);
    
        @Select("select small_img from cake where id = #{id} for update")
        Cake getImg(@Param("id")Long id);
    }

service类：CakeService

package com.imooc.cake.service;
    
    import com.imooc.cake.common.MyBatisUtils;
    import com.imooc.cake.entity.Cake;
    import com.imooc.cake.mapper.CakeMapper;
    import org.apache.ibatis.session.SqlSession;
    
    import java.util.List;
    
    public class CakeService {
    
        public List<Cake> getCakesByCategoryId(Long categoryId, Integer page, Integer size){
            SqlSession sqlSession = MyBatisUtils.openSession();
            try {
                CakeMapper mapper = sqlSession.getMapper(CakeMapper.class);
    
                return mapper.getCakesByCategoryId(categoryId, (page - 1) * size, size);
            }finally{
                sqlSession.close();
            }
        }
    
    }