Mybatis逆向工程

1.爲什麼使用mybatis逆向工程

mybaits需要程序員自己編寫sql語句,mybatis官方提供MyBatis Generator逆向工程,可以針對單表自動生成mybatis執行所需要的代碼（mapper.java,mapper.xml、po..）

2.Maven依賴逆向工程

   

<!--逆向工程依賴-->
<dependency>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-core</artifactId>
    <version>1.3.5</version>
</dependency>
<!-- 日誌 -->
	  <dependency>
	      <groupId>org.slf4j</groupId>
	      <artifactId>slf4j-api</artifactId>
	      <version>1.7.5</version>
	    </dependency>
	
	    <dependency>
	      <groupId>org.slf4j</groupId>
	      <artifactId>slf4j-log4j12</artifactId>
	      <version>1.7.12</version>
	    </dependency>
	
	    <dependency>
	      <groupId>log4j</groupId>
	      <artifactId>log4j</artifactId>
	      <version>1.2.17</version>
	    </dependency>
		
		
       <!-- 日誌 -->
	   <dependency>
	      <groupId>org.slf4j</groupId>
	      <artifactId>slf4j-api</artifactId>
	      <version>1.7.5</version>
	    </dependency>
	
	    <dependency>
	      <groupId>org.slf4j</groupId>
	      <artifactId>slf4j-log4j12</artifactId>
	      <version>1.7.12</version>
	    </dependency>
	
	    <dependency>
	      <groupId>log4j</groupId>
	      <artifactId>log4j</artifactId>
	      <version>1.2.17</version>
	    </dependency>
  	 <!-- mybatis 依賴 -->
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.4.5</version>
		</dependency>
		 <!-- mysql 依賴 -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.26</version>
		</dependency>

3. 生成代碼配置文件

  

<?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="testTables" targetRuntime="MyBatis3">
        <commentGenerator>
            <!-- 是否去除自動生成的註釋 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true" />
        </commentGenerator>
        <!--數據庫連接的信息：驅動類、連接地址、用戶名、密碼 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
            connectionURL="jdbc:mysql://120.25.162.238:3306/mybatis001?characterEncoding=utf-8" 
            userId="root"
            password="123">
        </jdbcConnection>
        <!-- <jdbcConnection driverClass="oracle.jdbc.OracleDriver"
            connectionURL="jdbc:oracle:thin:@127.0.0.1:1521:yycg" 
            userId="yycg"
            password="yycg">
        </jdbcConnection> -->

        <!-- 默認false，把JDBC DECIMAL 和 NUMERIC 類型解析爲 Integer，爲 true時把JDBC DECIMAL 和 
            NUMERIC 類型解析爲java.math.BigDecimal -->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- targetProject:生成PO類的位置 -->
        <javaModelGenerator targetPackage="com.iot.ssm.po"
            targetProject=".\src">
            <!-- enableSubPackages:是否讓schema作爲包的後綴 -->
            <property name="enableSubPackages" value="false" />
            <!-- 從數據庫返回的值被清理前後的空格 -->
            <property name="trimStrings" value="true" />
        </javaModelGenerator>
        <!-- targetProject:mapper映射文件生成的位置 -->
        <sqlMapGenerator targetPackage="com.iot.ssm.mapper" 
            targetProject=".\src">
            <!-- enableSubPackages:是否讓schema作爲包的後綴 -->
            <property name="enableSubPackages" value="false" />
        </sqlMapGenerator>
        <!-- targetPackage：mapper接口生成的位置 -->
        <javaClientGenerator type="XMLMAPPER"
            targetPackage="com.iot.ssm.mapper" 
            targetProject=".\src">
            <!-- enableSubPackages:是否讓schema作爲包的後綴 -->
            <property name="enableSubPackages" value="false" />
        </javaClientGenerator>
        <!-- 指定數據庫表 -->
        <table tableName="items"></table>
        <table tableName="orders"></table>
        <table tableName="orderdetail"></table>
        <table tableName="user"></table>
        <!-- <table schema="" tableName="sys_user"></table>
        <table schema="" tableName="sys_role"></table>
        <table schema="" tableName="sys_permission"></table>
        <table schema="" tableName="sys_user_role"></table>
        <table schema="" tableName="sys_role_permission"></table> -->

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

需要注意的位置：

 

javaModelGenerator,生成PO類的位置

sqlMapGenerator,mapper映射文件生成的位置

javaClientGenerator,mapper接口生成的位置

table,指定數據庫表

 

4. 執行生成程序

public void generator() throws Exception{

    List<String> warnings = new ArrayList<String>();

    boolean overwrite = true;

    //指定逆向工程配置文件

    InputStream configFile= Resources.getResourceAsStream("mybatis-generator.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);

}