Mybatis01

一、mybatis环境搭建

1、导入pom.xml依赖


 
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>ideamavenartifactId>
        <groupId>org.examplegroupId>
        <version>1.0-SNAPSHOTversion>
    parent>
    <modelVersion>4.0.0modelVersion>
 
    <artifactId>mybatis01artifactId>
    <packaging>warpackaging>
 
    <name>mybatis01 Maven Webappname>
    
    <url>http://www.example.comurl>
 
    <properties>
        <maven.compiler.source>1.8maven.compiler.source>
        <maven.compiler.target>1.8maven.compiler.target>
    properties>
 
    <dependencies>
        
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.12version>
            <scope>testscope>
        dependency>
 
        
        <dependency>
            <groupId>javax.servletgroupId>
            <artifactId>javax.servlet-apiartifactId>
            <version>4.0.0version>
            <scope>providedscope>
        dependency>
 
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.4.5version>
        dependency>
 
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.44version>
        dependency>
 
        
        
        
        
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-coreartifactId>
            <version>2.9.1version>
        dependency>
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-apiartifactId>
            <version>2.9.1version>
        dependency>
        
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-webartifactId>
            <version>2.9.1version>
        dependency>
    dependencies>
 
 
    <build>
        <finalName>mybatis01finalName>
        <resources>
            
            <resource>
                <directory>src/main/javadirectory>
                <includes>
                    <include>**/*.xmlinclude>
                includes>
            resource>
            
            <resource>
                <directory>src/main/resourcesdirectory>
                <includes>
                    <include>jdbc.propertiesinclude>
                    <include>*.xmlinclude>
                includes>
            resource>
        resources>
 
        <pluginManagement>
            <plugins>
 
                <plugin>
                    <groupId>org.mybatis.generatorgroupId>
                    <artifactId>mybatis-generator-maven-pluginartifactId>
                    <version>1.3.2version>
                    <dependencies>
                        
                        <dependency>
                            <groupId>mysqlgroupId>
                            <artifactId>mysql-connector-javaartifactId>
                            <version>5.1.44version>
                        dependency>
                    dependencies>
                    <configuration>
                        <overwrite>trueoverwrite>
                    configuration>
                plugin>
 
 
 
                <plugin>
                    <artifactId>maven-clean-pluginartifactId>
                    <version>3.1.0version>
                plugin>
                
                <plugin>
                    <artifactId>maven-resources-pluginartifactId>
                    <version>3.0.2version>
                plugin>
                <plugin>
                    <artifactId>maven-compiler-pluginartifactId>
                    <version>3.8.0version>
                plugin>
                <plugin>
                    <artifactId>maven-surefire-pluginartifactId>
                    <version>2.22.1version>
                plugin>
                <plugin>
                    <artifactId>maven-war-pluginartifactId>
                    <version>3.2.2version>
                plugin>
                <plugin>
                    <artifactId>maven-install-pluginartifactId>
                    <version>2.5.2version>
                plugin>
                <plugin>
                    <artifactId>maven-deploy-pluginartifactId>
                    <version>2.8.2version>
                plugin>
            plugins>
        pluginManagement>
    build>
project>

补全maven项目的目录，如图：

resources中jdbc.properties 数据库连接配置


jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8
jdbc.username=root
jdbc.password=123456

2、导入框架的配置文件

安装以下插件

Free mybatis plugin

Mybatis generator

mybatis tools

maven helper

详细介绍

Intellij Idea Mybatis 插件(plugin和tools插件）_yangshijin1988的博客-CSDN博客_idea mapper 插件

下载maven helper之后可以看到配置文件中所用的依赖

修改web.xml


<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
web-app>

mybatis.cfg.xml


configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    
    <properties resource="jdbc.properties"/>
 
    <settings>
        <setting name="logImpl" value="LOG4J2"/>
    settings>
 
    
    <typeAliases>
        
    typeAliases>
 
 
    
    <environments default="development">
        <environment id="development">
            
            <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>
       
    mappers>
configuration>

二、Mybatis generator插件的使用

基于ssm的逆向工程使用

安装Mybatis generator插件已下载安装好
配置generatorConfig.xml
配置maven运行generator命令
在pom中处理generatorConfig.xml不能编译问题

generatorConfig.xml


generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
<generatorConfiguration>
    
    <properties resource="jdbc.properties"/>
 
    
    <classPathEntry location="E:\\cdl_mvn_repository\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/>
 
    
    <context id="infoGuardian">
        
        <commentGenerator>
            <property name="suppressAllComments" value="true"/>
            <property name="suppressDate" value="true"/> 
        commentGenerator>
 
        
        <jdbcConnection driverClass="${jdbc.driver}"
                        connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/>
 
        
        <javaTypeResolver>
            
            <property name="forceBigDecimals" value="false"/>
        javaTypeResolver>
 
        
        
        
        <javaModelGenerator targetPackage="com.cdl.model"
                            targetProject="src/main/java">
            
            <property name="enableSubPackages" value="false"/>
            
            <property name="constructorBased" value="true"/>
            
            <property name="trimStrings" value="false"/>
            
            <property name="immutable" value="false"/>
        javaModelGenerator>
 
        
        <sqlMapGenerator targetPackage="com.cdl.mapper"
                         targetProject="src/main/java">
            
            <property name="enableSubPackages" value="false"/>
        sqlMapGenerator>
 
        
        
        
        
        <javaClientGenerator targetPackage="com.cdl.mapper"
                             targetProject="src/main/java" type="XMLMAPPER">
            
            <property name="enableSubPackages" value="false"/>
        javaClientGenerator>
 
        
        
        
        
        
        
        
        
        
        
        
        
        
 
        <table schema="" tableName="t_mvc_Book" domainObjectName="Book"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
            
            
            
            
        table>
 
 
        <table schema="" tableName="t_oa_permission" domainObjectName="Permission"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        table>
 
    context>
generatorConfiguration>

写命令

写入命令

结果

写入命令后运行会自动将数据库的表、字段名映射成对应的类名和属性名

并且生成增删改查的方法

总结一下：

1.添加配置文件

1.1 修改5.1.44的jar的路径

1.2 修改实体类生成的地址

1.3 修改SQL对应的配置文件的生成地址

1.4修改Dao层代码地址

1.5指定需要生成增删改查代码对应的表

2.配置maven的mybatis逆向生成代码的命令

commond line

3.在pom文件中使用配置好的命令

三、Mybatis增删改查测试

sqlsession的作用:

1.sqlsession可以拿到mapper对象

2.作为缓存使用，一级缓存，默认会开启的缓存、

3.出于对性能的考虑，会采用二级缓存，二级缓存需要手动开启

测试逆向生成的代码是否正确

有事务的：增删改

无事务的：查询

只需要测查询和删除即可知道是否正确

建一个com.cdl.biz.impl的包


package com.cdl.biz;
 
import com.cdl.model.Book;
 
/**
 * @author cdl
 * @site www.cdl.com
 * @create 2022-08-10 22:00
 */
public interface BookBiz {
 
    int deleteByPrimaryKey(Integer bid);
 
 
    Book selectByPrimaryKey(Integer bid);
 
 
}

com.cdl.util

SessionUtil


package com.cdl.util;
 
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 
/**
 * @author cdl
 * @site www.cdl.com
 * @create 2022-08-10 22:47
 */
public class SessionUtil {
    private static SqlSessionFactory sessionFactory;
    private static ThreadLocal threadLocal = new ThreadLocal();
    static {
        sessionFactory = new SqlSessionFactoryBuilder().build(SessionUtil.class.getResourceAsStream("/mybatis.cfg.xml"));
    }
 
    public static SqlSession openSession() {
        SqlSession session = threadLocal.get();
        if (null == session) {
            session = sessionFactory.openSession();
            threadLocal.set(session);
        }
        return session;
    }
 
    public static void main(String[] args) {
        SqlSession session = openSession();
        System.out.println(session.getConnection());
        session.close();
//        System.out.println(session.getConnection());
    }
}

//alt + insert 快速提供set/get/tostring/构造函数
//alt +enter 快速构建实现类 能够自动补全

test类：


package com.cdl.biz.impl;
 
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
 
import static org.junit.Assert.*;
 
/**
 * @author cdl
 * @site www.cdl.com
 * @create 2022-08-10 22:55
 */
public class BookBizImplTest {
 
    @Before
    public void setUp() throws Exception {
        System.out.println("初始换方法。。。");
    }
 
    @After
    public void tearDown() throws Exception {
        System.out.println("方法测试结束。。");
    }
 
    @Test
    public void deleteByPrimaryKey() {
    }
 
    @Test
    public void selectByPrimaryKey() {
        System.out.println("测试的业务方法。。。");
    }
 
}

运行结果：

修改配置文件 mybatis.cfg.xml
   

测试类：


package com.cdl.biz.impl;
 
import com.cdl.mapper.BookMapper;
import com.cdl.util.SessionUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
 
/**
 * @author cdl
 * @site www.cdl.com
 * @create 2022-08-10 22:55
 */
public class BookBizImplTest {
 
    private BookBizImpl bookBiz;
    SqlSession sqlSession;
 
    @Before
    public void setUp() throws Exception {
        System.out.println("初始换方法。。。");
      BookBizImpl  bookBiz = new BookBizImpl();
      //工具类中获取session对象
      sqlSession = SessionUtil.openSession();
     //从session对象中获取mapper对象
      BookMapper mapper = sqlSession.getMapper(BookMapper.class);
        bookBiz.setBookMapper(mapper);
        this.bookBiz = bookBiz;
    }
 
    @After
    public void tearDown() throws Exception {
        System.out.println("方法测试结束。。");
    }
 
    @Test
    public void deleteByPrimaryKey() {
    }
 
    @Test
    public void selectByPrimaryKey() {
 
        System.out.println("测试的业务方法。。。");
        //System.out.println(bookBiz.getBookMapper());
        System.out.println(bookBiz.selectByPrimaryKey(44));
    }
 
}

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原文地址：https://blog.csdn.net/weixin_62735525/article/details/126263287