版权声明： https://blog.csdn.net/weixin_40521823/article/details/84843738
一、导入或者创建逆向工程
- 导入的工程如下所示
2.新建lib文件夹，导jar包，如下所示
3.注意配置文件generatorConfig.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="testTables" targetRuntime="MyBatis3">
<commentGenerator>
<!-- 是否去除自动生成的注释 true：是 ： false:否 -->
<property name="suppressAllComments" value="true" />
</commentGenerator>
<!--数据库连接的信息：驱动类、连接地址、用户名、密码 -->
<jdbcConnection driverClass="com.mysql.jdbc.Driver"
connectionURL="jdbc:mysql://localhost:3306/mybatis" userId="root"
password="root">
</jdbcConnection>
<!-- <jdbcConnection driverClass="oracle.jdbc.OracleDriver"
connectionURL="jdbc:oracle:thin:@127.0.0.1:1521:yycg"
userId="yycg"
password="yycg">
</jdbcConnection> -->
<!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer，为 true时把JDBC DECIMAL 和
NUMERIC 类型解析为java.math.BigDecimal -->
<javaTypeResolver>
<property name="forceBigDecimals" value="false" />
</javaTypeResolver>
<!-- targetProject:生成PO类的位置 -->
<javaModelGenerator targetPackage="com.itheima.mybatis.pojo"
targetProject=".\src">
<!-- enableSubPackages:是否让schema作为包的后缀 -->
<property name="enableSubPackages" value="false" />
<!-- 从数据库返回的值被清理前后的空格 -->
<property name="trimStrings" value="true" />
</javaModelGenerator>
<!-- targetProject:mapper映射文件生成的位置 -->
<sqlMapGenerator targetPackage="com.itheima.mybatis.mapper"
targetProject=".\src">
<!-- enableSubPackages:是否让schema作为包的后缀 -->
<property name="enableSubPackages" value="false" />
</sqlMapGenerator>
<!-- targetPackage：mapper接口生成的位置 -->
<javaClientGenerator type="XMLMAPPER"
targetPackage="com.itheima.mybatis.mapper"
targetProject=".\src">
<!-- enableSubPackages:是否让schema作为包的后缀 -->
<property name="enableSubPackages" value="false" />
</javaClientGenerator>
<!-- 指定数据库表 -->
<table schema="" tableName="user"></table>
<table schema="" tableName="orders"></table>
<!-- 有些表的字段需要指定java类型
<table schema="" tableName="">
<columnOverride column="id" javaType="Long" />
</table> -->
</context>
</generatorConfiguration>
4.注意default包下的java文件--generatorSqlMap.java文件
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 GeneratorSqlmap { public void generator() throws Exception{ List<String> warnings = new ArrayList<String>(); boolean overwrite = true; //指定逆向工程配置文件 File configFile = new File("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); } public static void main(String[] args) throws Exception { try { GeneratorSqlmap generatorSqlmap = new GeneratorSqlmap(); generatorSqlmap.generator(); } catch (Exception e) { e.printStackTrace(); } } }
5.sql表有两张，是user和orders表。
user表
orders表
6.运行generatorSqlMap.java文件，利用逆向工程生成的pojo和mapper文件如下所示：
二、将自动生成的文件，copy到新的java工程文件中，进行接下来操作-------测试逆向工程代码
1、applicationContext.xml文件配置：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">
<context:property-placeholder location="classpath:db.properties"/>
<!-- dbcp 数据源 -->
<!-- 数据库连接池 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<property name="maxActive" value="10" />
<property name="maxIdle" value="5" />
</bean>
<!-- Mybatis的工厂 -->
<bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<!-- 核心配置文件的位置 -->
<property name="configLocation" value="classpath:sqlMapConfig.xml"/>
</bean>
<!-- 动态代理开发增强版 扫描 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 指定基本包 -->
<property name="basePackage" value="com.itheima.mybatis.mapper"/>
</bean>
</beans>2、编写测试方法
public class JunitTest {
private ApplicationContext ac;
@Test
public void testMapper() throws Exception{
ac = new ClassPathXmlApplicationContext("applicationContext.xml");
UserMapper userMapper = ac.getBean(UserMapper.class);
UserExample example = new UserExample();
String username = "明";
example.createCriteria().andSexEqualTo("1").andUsernameLike("%" + username + "%");
example.setOrderByClause("id desc");
//按照条件进行统计
int countByExample = userMapper.countByExample(example);
System.out.println(countByExample);
User user = userMapper.selectByPrimaryKey(10);
System.out.println(user);
//按照条件进行查询
List<User> users = userMapper.selectByExample(example);
for (User user2 : users) {
System.out.println(user2.getId());
}
List<User> list = userMapper.selectByExample(example);
System.out.println(list.size());
}
}