MyBatis的增删改查基本操作

ゝ一世哀愁。 2022-07-15 04:11 259阅读 0赞

> ## MyBatis和Hibernate的使用基本一样，区别在于Hibernate在Java代码中实现数据库操作，集成度高；Mybatis在注解或者xml文件中通过配置实现SQL语句，更加灵活 ##

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## 创建使用MyBatis的Java项目 ##

## 1. 创建并配置 ##

*  创建Java项目并引入[MyBaits的jar文件][MyBaits_jar]
 *  配置log4j.properties（用于查看执行的SQL语句，日志等）

log4j.rootLogger=DEBUG,Console
    
    log4j.appender.Console=org.apache.log4j.ConsoleAppender
    log4j.appender.Console.layout=org.apache.log4j.PatternLayout
    log4j.appender.Console.layout.ConversionPattern=%d[%t]%-5p[%c]-%m%n
    
    log4j.logger.java.sql.ResultSet=INFO
    log4j.logger.org.apache=INFO
    log4j.logger.java.sql.Connection=DEBUG
    log4j.logger.java.sql.Statement=DEBUG
    log4j.logger.java.sql.PreparedStatement=DEBUG

*  配置MyBaits的配置文件

<?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>
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC" />
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver" />
                    <property name="url" value="jdbc:mysql://localhost/mybatis?useSSL=false" />
                    <property name="username" value="root" />
                    <property name="password" value="123456" />
                </dataSource>
            </environment>
        </environments>
        
        <mappers>
            <mapper resource="map/query.xml" />
            <mapper resource="map/insert.xml" />
            <mapper resource="map/update.xml" />
            <mapper resource="map/delete.xml" />
        </mappers>
    </configuration>

## 2.实现增删改查操作 ##

*  创建和数据库表对应的JavaBean
 *  创建相应的文件
 *  通过Java中调用实现相关操作

//加载配置文件并初始化
    public class InsertTest { 
        public static void main(String[] args) {
            String resource = "map/mybatis.xml";
    
            Reader reader = null;
            SqlSessionFactory factory = null;
            SqlSession session = null;
    
            try {
                reader = Resources.getResourceAsReader(resource);
                factory = new SqlSessionFactoryBuilder().build(reader);
                session = factory.openSession();
    
                /** *具体功能实现部分 **/
    
                session.commit();
            } catch (IOException e) {
                session.rollback();
                e.printStackTrace();
            } finally {
                session.close();
            }
    
        }
    }

*  insert.xml

<insert id="insert" parameterType="pojo.User" statementType="PREPARED" keyProperty="id" useGeneratedKeys="true">
            insert into mybatis(name,password)
            values(#{name},#{password})
        </insert>

*  insert实现

User user = new User(1, "果粒橙", "果粒橙");
        session.insert("insert", user);

*  delete.xml

<delete id="deleteByObject" parameterType="pojo.User">
            delete from mybatis
            where id = #{id}
        </delete>
        <delete id="deleteByID" parameterType="int">
            delete from mybatis where
            id = #{id}
        </delete>

*  delete实现

// 通过对象删除
            User user = new User();
            user.setId(3);
            session.delete("deleteByObject", user);
    
            // 通过ID删除
            session.delete("deleteByID", 2);

*  update.xml

<update id="update" parameterType="pojo.User">
            update mybatis set name=#{name},password=#{password}
            where id = #{id}
        </update>

*  update实现

User user = new User(3, "益达", "你的益达");
        session.update("update", user);

*  query.xml

<select id="queryUser" resultType="pojo.User">
            select * from mybatis where id = #{id}
        </select>
    
        
        <select id="queryUsers" resultType="pojo.User">
            select * from mybatis
        </select>
    
        
        <resultMap type="pojo.User" id="queryResultMap">
            <id column="id" property="id"></id>
            <result property="name" column="name" />
            <result property="password" column="password" />
        </resultMap>
        <select id="queryMap" resultMap="queryResultMap">
            select * from mybatis
        </select>

*  query实现

// 返回一个查询结果,返回resultType
        User user = session.selectOne("queryUser", 1);
        System.out.println(user.getName());
    
        // 返回多个查询结果,返回resultType
        List<User> results = session.selectList("queryUsers");
        for (User user1 : results) {
            System.out.println(user1.getName() + "---" + user1.getPassword());
        }
    
        // 返回多个结果,返回resultMap
        List<User> results1 = session.selectList("queryMap");
        for (User user2 : results1) {
            System.out.println(user2.getName() + "---" + user2.getPassword());
        }

*  表  
    ![表][20161101202926337]

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## [项目下载][Link 1] ##

[MyBaits_jar]: http://download.csdn.net/detail/u013360850/9670393
[20161101202926337]: /images/20220715/b1fdadec641a4f7da8bc7d8e007aa499.png
[Link 1]: http://download.csdn.net/detail/u013360850/9670399