mybatis之generator简单入门

清疚 2024-04-17 20:18 53阅读 0赞

# 一、generator简介 #

MyBatis Generator（MBG）是MyBatis MyBatis 和iBATIS的代码生成器。它将为所有版本的MyBatis以及版本2.2.0之后的iBATIS版本生成代码。它将内省数据库表（或许多表），并将生成可用于访问表的工件。这减少了设置对象和配置文件以与数据库表交互的初始麻烦。MBG寻求对简单CRUD（创建，检索，更新，删除）的大部分数据库操作产生重大影响。（一句话，generator可以自动生成代码和映射文件，但是多表查询还是需要我们去配置，即使这样也可以省很多功夫）

# 二、generator配置 #

[generator官网:http://www.mybatis.org/generator/index.html][generator_http_www.mybatis.org_generator_index.html]

### 1.导包（后面跟mybatis整合，所以顺便把mybatis的包也导了） ###

<properties>
      	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      		<junit.version>4.12</junit.version>
      		<slf4j.version>1.7.25</slf4j.version>
      		<javax.servlet.jsp-api.version>2.3.1</javax.servlet.jsp-api.version>
    		<javax.servlet-api.version>3.1.0</javax.servlet-api.version>
      		<mysql.version>5.1.38</mysql.version>
      		<mybatis.version>3.4.6</mybatis.version>
      		<mybatis-generator-core.version>1.3.7</mybatis-generator-core.version>
      </properties>
      <dependencies>
      
      <dependency>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-core</artifactId>
        <version>${mybatis-generator-core.version}</version>
    </dependency>
      
      <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>${mybatis.version}</version>
    </dependency>
        	
    	<dependency>
    	    <groupId>mysql</groupId>
    	    <artifactId>mysql-connector-java</artifactId>
    	    <version>${mysql.version}</version>
    	</dependency>
    	
    		<dependency>
    			<groupId>javax.servlet.jsp</groupId>
    			<artifactId>javax.servlet.jsp-api</artifactId>
    			<version>${javax.servlet.jsp-api.version}</version>
    			<scope>provided</scope>
    		</dependency>
    		<dependency>
    			<groupId>javax.servlet</groupId>
    			<artifactId>javax.servlet-api</artifactId>
    			<version>${javax.servlet-api.version}</version>
    			<scope>provided</scope>
    		</dependency>
    		
    	<dependency>
    	    <groupId>org.slf4j</groupId>
    	    <artifactId>slf4j-log4j12</artifactId>
    	    <version>${slf4j.version}</version>
    	    <scope>test</scope>
    	</dependency>
      
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>${junit.version}</version>
          <scope>test</scope>
        </dependency>
      </dependencies>

### 2.generator-config.xml ###

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE generatorConfiguration
      PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
      "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
    
    <generatorConfiguration>
      
      <context id="MyGnerator" targetRuntime="MyBatis3">
      
      <commentGenerator>
      	
        	<property name="suppressAllComments" value="true"/>
        
        	<property name="suppressDate" value="true"/>
        </commentGenerator>
        
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
            connectionURL="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8"
            userId="blog"
            password="blog">
        </jdbcConnection>
    
      
    
        <javaModelGenerator targetPackage="com.mybatis_generator_demo.domain" targetProject="src/main/java">
        
          <property name="enableSubPackages" value="false" />
          
          <property name="trimStrings" value="true" />
        </javaModelGenerator>
    
        <sqlMapGenerator targetPackage="com.mybatis_generator_demo.mapper"  targetProject="src/main/java">
          <property name="enableSubPackages" value="false" />
        </sqlMapGenerator>
    
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.mybatis_generator_demo.mapper"  targetProject="src/main/java">
          <property name="enableSubPackages" value="false" />
        </javaClientGenerator>
    
    <table tableName="t_user"/>
    
        
    
      </context>
    </generatorConfiguration>

### 3.启动generator ###

package com.mybatis_generator_demo.geberator;
    
    import java.io.File;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.mybatis.generator.api.MyBatisGenerator;
    import org.mybatis.generator.config.Configuration;
    import org.mybatis.generator.config.xml.ConfigurationParser;
    import org.mybatis.generator.internal.DefaultShellCallback;
    
    public class generator {
    	public static void main(String[] args) {
    		try {
    			List<String> warnings = new ArrayList<String>();
    			boolean overwrite = true;
    			File configFile = new File("src/main/resources/generatorConfig.xml");
    			ConfigurationParser cp = new ConfigurationParser(warnings);
    			Configuration config = cp.parseConfiguration(configFile);
    			DefaultShellCallback callback = new DefaultShellCallback(overwrite);
    			MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
    			myBatisGenerator.generate(null);
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    }

### 4.运行结果 ###

运行前：什么代码都没有，只有一个generator启动代码  
![在这里插入图片描述][20190831133337799.png]  
运行后：数据库表对应的实体类和mapper接口以及mapper.xml文件  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NoT0xn_size_16_color_FFFFFF_t_70]

# 三、与mybatis整合到一起 #

### 1.db.properties(需要修改为自己的数据库和用户信息) ###

dataSource.driver=com.mysql.jdbc.Driver
    dataSource.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8
    dataSource.username=blog
    dataSource.password=blog

### 2.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>
    
    	<properties resource="db.properties"></properties>
    	
    	<typeAliases>
    		
    		
    	 	
    	 	<package name="com.mybatis_generator_demo.domain"/>
    	 </typeAliases>
    
      <environments default="development">
      
        <environment id="development">
        
          <transactionManager type="JDBC"/>
          
          <dataSource type="POOLED">
            <property name="driver" value="${dataSource.driver}"/>
            <property name="url" value="${dataSource.url}"/>
            <property name="username" value="${dataSource.username}"/>
            <property name="password" value="${dataSource.password}"/>
          </dataSource>
        </environment>
      </environments>
      
      <mappers>
      
       
        
        
        
        
        
       
        <package name="com.mybatis_generator_demo.mapper"/>
      </mappers>
    </configuration>

### 3.测试代码(简单测试了几个方法，generator提供了丰富的单表操作方法，需要再研究研究) ###

package com.mybatis_generator_demo.test;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.ArrayList;
    import java.util.List;
    
    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 org.junit.Test;
    
    import com.mybatis_generator_demo.domain.TUser;
    import com.mybatis_generator_demo.domain.TUserExample;
    import com.mybatis_generator_demo.domain.TUserExample.Criteria;
    import com.mybatis_generator_demo.mapper.TUserMapper;
    
    public class TestMapper {
    	//条件删除用户
    	@Test
    	public void test_delete() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUserExample example = new TUserExample();
    			example.createCriteria().andUidBetween(50, 60);
    			int result = mapper.deleteByExample(example);
    			session.commit();
    			if(result>0) System.out.println("success");
    			else System.out.println("failure");
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	//根据id集合查询用户信息
    	@Test
    	public void test_andUidIn() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUserExample example = new TUserExample();
    			List<Integer> list = new ArrayList<Integer>();
    			list.add(1);
    			list.add(5);
    			list.add(108);
    			list.add(53);
    			example.createCriteria().andUidIn(list);
    			List<TUser> users = mapper.selectByExample(example);
    			for (TUser tUser : users) {
    				System.out.println(tUser);
    			}
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	//条件更新用户信息
    	@Test
    	public void test_updateByExample() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUserExample example = new TUserExample();
    			example.createCriteria().andUnameEqualTo("测试插入");
    			TUser u = new TUser();
    			u.setAddress("广东");
    			u.setAge(225);
    			u.setUname("李飞");
    			int result = mapper.updateByExampleSelective(u, example);
    			if(result>0) System.out.println("success");
    			else System.out.println("failure");
    			session.commit();
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	//多条件or查询
    	@Test
    	public void test_selectByExample2() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUserExample example = new TUserExample();
    			example.createCriteria().andAgeBetween(1, 10).andAddressLike("%北京%");
    			Criteria c2 = example.createCriteria().andUnameEqualTo("老王");
    			example.or(c2);
    			List<TUser> list = mapper.selectByExample(example);
    			for (TUser tUser : list) {
    				System.out.println(tUser);
    			}
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	
    	//多条件and查询
    	@Test
    	public void test_selectByExample() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUserExample example = new TUserExample();
    			example.createCriteria().andAgeBetween(1, 10).andAddressLike("%北京%");
    			List<TUser> list = mapper.selectByExample(example);
    			for (TUser tUser : list) {
    				System.out.println(tUser);
    			}
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	//插入用户到数据库
    	@Test
    	public void test_insert() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUser u = new TUser();
    			u.setAddress("四川");
    			u.setAge(22);
    			u.setUname("测试插入");
    			int result = mapper.insert(u);
    			if(result>0) System.out.println("success");
    			else System.out.println("failure");
    			session.commit();
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	//根据主键获取用户信息
    	@Test
    	public void test_selectByPrimaryKey() {
    		 try {
    			InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
    			SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
    			SqlSessionFactory sqlSessionFactory = builder.build(in);
    			SqlSession session = sqlSessionFactory.openSession();
    			TUserMapper mapper = session.getMapper(TUserMapper.class);
    			TUser TUser = mapper.selectByPrimaryKey(3);
    			System.out.println(TUser);
    		 } catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    }

[generator_http_www.mybatis.org_generator_index.html]: http://www.mybatis.org/generator/index.html
[20190831133337799.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/76bc17a66e994ef7bd3f413ced29bebc.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NoT0xn_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/25421f9e241c4fe7a748f9fcbd7117de.png