Mybatis---MBG-逆向工程(五)

短命女 2021-09-23 16:18 276阅读 0赞

# 逆向工程 #

**正向：**  
table----javaBean—BookDao—dao.xml—xxx  
**逆向工程：**  
根据数据表table，逆向分析数据表，自动生成javaBean—BookDao—dao.xml—xxx

**MBG：MyBatis Generator：代码生成器；  
MyBatis官方提供的代码生成器；帮我们逆向生成；**

## 1、导包：mbg的核心包 ##

## 2、编写mbg.xml配置文件 ##

<?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="DB2Tables" targetRuntime="MyBatis3">
            <commentGenerator>
                <property name="suppressAllComments" value="true"/>
            </commentGenerator>
            
            <jdbcConnection
    
                driverClass="com.mysql.jdbc.Driver"
                connectionURL="jdbc:mysql://localhost:3306/mybatis_0325"
    
                userId="root"
    
                password="123456">
            </jdbcConnection>
    
            <javaTypeResolver>
                <property name="forceBigDecimals" value="false" />
            </javaTypeResolver>
    
            
            <javaModelGenerator targetPackage="com.atguigu.bean"
                targetProject=".\src">
                <property name="enableSubPackages" value="true" />
                <property name="trimStrings" value="true" />
            </javaModelGenerator>
    
            
            <sqlMapGenerator targetPackage="com.atguigu.dao"
                targetProject=".\conf">
                <property name="enableSubPackages" value="true" />
            </sqlMapGenerator>
    
            
            <javaClientGenerator type="XMLMAPPER"
                targetPackage="com.atguigu.dao"
    
                targetProject=".\src">
                <property name="enableSubPackages" value="true" />
            </javaClientGenerator>
    
            
            <table tableName="t_cat" domainObjectName="Cat"></table>
            <table tableName="t_employee" domainObjectName="Employee"></table>
            <table tableName="t_teacher" domainObjectName="Teacher"></table>
    
        </context>
    </generatorConfiguration>

## 3、运行代码生成 ##

package com.atguigu.test;
    
    import java.io.File;
    import java.io.IOException;
    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.exception.XMLParserException;
    import org.mybatis.generator.internal.DefaultShellCallback;
    
    public class MBGTest { 
    
        public static void main(String[] args) throws Exception { 
            List<String> warnings = new ArrayList<String>();
            boolean overwrite = true;
            File configFile = new File("mbg.xml");
            ConfigurationParser cp = new ConfigurationParser(warnings);
            Configuration config = cp.parseConfiguration(configFile);
            DefaultShellCallback callback = new DefaultShellCallback(overwrite);
            MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
                    callback, warnings);
            //代码生成
            myBatisGenerator.generate(null);
            System.out.println("生成ok了！");
        }
    
    }

## 4、测试复杂查询 ##

package com.atguigu.test;
    
    import static org.junit.Assert.*;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import java.util.UUID;
    
    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.Before;
    import org.junit.Test;
    
    import com.atguigu.bean.Teacher;
    import com.atguigu.bean.TeacherExample;
    import com.atguigu.bean.TeacherExample.Criteria;
    import com.atguigu.dao.TeacherMapper;
    
    
    
    public class MyBatisTest { 
    
        // 工厂一个
        SqlSessionFactory sqlSessionFactory;
    
    
        @Test
        public void test02(){ 
            SqlSession sqlSession = sqlSessionFactory.openSession();
            //1、测试
            TeacherMapper mapper = sqlSession.getMapper(TeacherMapper.class);
            List<Teacher> teachers = new ArrayList<Teacher>();
            for (int i = 0; i < 1000; i++) { 
                Teacher teacher = new Teacher();
                teacher.setTeachername(UUID.randomUUID().toString().substring(0, 5));
                teacher.setClassName(UUID.randomUUID().toString().substring(0, 5));
                teachers.add(teacher);
            }
            System.out.println("批量保存.....");
            mapper.insertBatch(teachers);
            sqlSession.commit();
            sqlSession.close();
    
    
        }
    
        /** * 测试代码生成器 * @throws IOException */
        @Test
        public void test01(){ 
            SqlSession sqlSession = sqlSessionFactory.openSession();
            //1、测试
            TeacherMapper mapper = sqlSession.getMapper(TeacherMapper.class);
            //2、测试查询所有teacher
            List<Teacher> list = mapper.selectByExample(null);
            for (Teacher teacher : list) { 
                System.out.println(teacher);
            }
    
            //3、带复杂条件的查询
            //select * from t_teacher id=? and teacherName like ?
            //封装查询条件的
            TeacherExample example = new TeacherExample();
            example.setOrderByClause("id DESC");
            //1、使用example创建一个Criteria（查询准则）
            Criteria criteria = example.createCriteria();
            criteria.andIdEqualTo(1);
            criteria.andTeachernameLike("%a%");
    
            System.out.println("======================");
            List<Teacher> list2 = mapper.selectByExample(example);
            for (Teacher teacher : list2) { 
                    System.out.println(teacher);
            }
    
            /** * 多个复杂条件 * select * from t_teacher where (id=? and teacherName like ?) or (address like ? and birth bet) */
            TeacherExample example2 = new TeacherExample();
    
    
            //一个Criteria能封装一整个条件
            Criteria criteria2 = example2.createCriteria();
            criteria2.andIdGreaterThan(1);
            criteria2.andTeachernameLike("%a%");
    
            //创建第二个查询条件
            Criteria criteria3 = example2.createCriteria();
            criteria3.andAddressLike("%%");
            criteria3.andBirthDateBetween(new Date(), new Date());
    
            example2.or(criteria3);
            System.out.println("=======-=-=-=-=-=-=-");
            mapper.selectByExample(example2);
    
        }
    
        @Before
        public void initSqlSessionFactory() throws IOException { 
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        }
    
    }