mybatis-generator的使用

关于mybatis-generator的使用步骤

1. 首先mybatis中的手写mapper.xml文件非常麻烦，所以我们可以使用mybatis-generator这个插件自动生成mapper文件以及bean类还有dao层接口。
2. 创建一个maven项目，在pom文件中插入以下依赖配置：

<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.briup</groupId>
	<artifactId>estore2</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<name>estore2</name>
	<dependencies>
		<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>8.0.20</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.mybatis.generator/mybatis-generator-core -->
		<dependency>
			<groupId>org.mybatis.generator</groupId>
			<artifactId>mybatis-generator-core</artifactId>
			<version>1.3.7</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.5.2</version>
		</dependency>

	</dependencies>
	<build>
		<plugins>
			<plugin>
				<groupId>org.mybatis.generator</groupId>
				<artifactId>mybatis-generator-maven-plugin</artifactId>
				<version>1.3.7</version>
				<configuration>
					<configurationFile>src/main/resources/generatorConfig.xml
					</configurationFile>
					<overwrite>true</overwrite>
				</configuration>
			</plugin>

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.1</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
				</configuration>
				<dependencies>
					<!-- jdbc 依赖 -->
					<dependency>
						<groupId>mysql</groupId>
						<artifactId>mysql-connector-java</artifactId>
						<version>8.0.20</version>
					</dependency>
				</dependencies>
			</plugin>
		</plugins>


	</build>
</project>

3. 然后在resources文件目录下书写generatorConfig.xml文件，如下所示：

<?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>
	<classPathEntry
		location="D:/repository/mysql/mysql-connector-java/8.0.20/mysql-connector-java-8.0.20.jar"/>
	<context id="testTables" targetRuntime="MyBatis3Simple">
		<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.cj.jdbc.Driver"
			connectionURL="jdbc:mysql://localhost:3306/estore?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"
			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.briup.bean"
			targetProject=".\src\main\java">
			<!-- 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="mapper"
			targetProject=".\src\main\resources">
			<!-- 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.briup.dao" targetProject=".\src\main\java">
			<!-- 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="Book" tableName="book"></table>
		<table schema="Category" tableName="category"></table>
		<table schema="Customer" tableName="customer"></table>
		<table schema="Order" tableName="order"></table>
		<table schema="OrderLine" tableName="orderline"></table>
		<table schema="ShopCar" tableName="shopcar"></table>

		<!-- 有些表的字段需要指定java类型 <table schema="" tableName=""> <columnOverride column="" 
			javaType="" /> </table> -->
	</context>
</generatorConfiguration>

4. 然后右键项目名–>run as–>maven build…–>写入命令参数mybatis-generator:generate执行即可。