使用MyBatis Generator自動生成實體、mapper和dao層

　　通過MyBatis Generator可以自動生成實體、mapper和dao層，記錄一下怎么用的。

主要步驟：　　

　　關於mybatis從數據庫反向生成實體、DAO、mapper:
　　參考文章：http://www.cnblogs.com/wangkeai/p/6934683.html
第一種方式：main方法運行（推薦）
　　1.在pom.xml中加入插件依賴：
　　2.寫mbgConfiguration.xml文件，jdbc.properties文件
　　3.寫/SSM/src/main/java/main/GenMain.java main方法
　　4.運行main函數，刷新

具體步驟：

　　1.在pom.xml中加入插件依賴（需要mybatis的包和反向生成的包）：

<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->

<dependency>

    <groupId>org.mybatis</groupId>

    <artifactId>mybatis</artifactId>

    <version>3.4.4</version>

</dependency>

<!-- mybatis-generator-core 反向生成java代碼-->

<dependency>

    <groupId>org.mybatis.generator</groupId>

    <artifactId>mybatis-generator-core</artifactId>

    <version>1.3.5</version>

</dependency>

　　2、寫mbgConfiguration.xml文件，jdbc.properties文件

　　mbgConfiguration.xml：里面的一些配置也是“因人而異”哦，需要適當修改。文件最后<table></table>就是對數據庫中的表作的對應，具體可以看篇頭的推薦文章或自己百度。

<?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">    

<!-- 第一種mybatis逆向生成xml配置 -->

<generatorConfiguration> 
   
    <properties resource="jdbc.properties" />  
  
    <context id="sqlserverTables" targetRuntime="MyBatis3">    

        <!-- 生成的pojo，將implements Serializable-->    
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin"></plugin>    

        <commentGenerator>    

            <!-- 是否去除自動生成的注釋 true：是 ： false:否 -->
    
            <property name="suppressAllComments" value="true" />    

        </commentGenerator>    


    <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 數據庫鏈接URL、用戶名、密碼 </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">jdbcConnection </span><span style="color: #ff0000">driverClass</span><span style="color: #0000ff">="${jdbc.driver}"</span><span style="color: #ff0000">    </br>
                    connectionURL</span><span style="color: #0000ff">="${jdbc.url}"</span><span style="color: #ff0000">    </br>
                    userId</span><span style="color: #0000ff">="${jdbc.username}"</span><span style="color: #ff0000">    </br>
                    password</span><span style="color: #0000ff">="${jdbc.password}"</span><span style="color: #0000ff">&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">jdbcConnection</span><span style="color: #0000ff">&gt;</span>    </br></br>

    <span style="color: #008000">&lt;!--</span><span style="color: #008000">      </br>
    默認false，把JDBC DECIMAL 和 NUMERIC 類型解析為 Integer    </br>
        true，把JDBC DECIMAL 和 NUMERIC 類型解析為java.math.BigDecimal </br>     
    </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">javaTypeResolver</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="forceBigDecimals"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="false"</span> <span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">javaTypeResolver</span><span style="color: #0000ff">&gt;</span> </br></br>   

    <span style="color: #008000">&lt;!--</span><span style="color: #008000">     </br>
    生成model模型，對應的包路徑，以及文件存放路徑(targetProject)，targetProject可以指定具體的路徑,如./src/main/java，    </br>
    也可以使用“MAVEN”來自動生成，這樣生成的代碼會在target/generatord-source目錄下    </br>
    </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #008000">&lt;!--</span><span style="color: #008000">&lt;javaModelGenerator targetPackage="com.joey.mybaties.test.pojo" targetProject="MAVEN"&gt;</span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">javaModelGenerator </span><span style="color: #ff0000">targetPackage</span><span style="color: #0000ff">="com.yyc.entity"</span><span style="color: #ff0000"> targetProject</span><span style="color: #0000ff">="./src/main/java"</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="enableSubPackages"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span><span style="color: #0000ff">/&gt;</span>    </br>
        <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 從數據庫返回的值被清理前后的空格  </span><span style="color: #008000">--&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="trimStrings"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span> <span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">javaModelGenerator</span><span style="color: #0000ff">&gt;</span>    </br></br>

    <span style="color: #008000">&lt;!--</span><span style="color: #008000">對應的mapper.xml文件  </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">sqlMapGenerator </span><span style="color: #ff0000">targetPackage</span><span style="color: #0000ff">="mappers"</span><span style="color: #ff0000"> targetProject</span><span style="color: #0000ff">="./src/main/resources"</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="enableSubPackages"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span><span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">sqlMapGenerator</span><span style="color: #0000ff">&gt;</span>    </br></br>

    <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 對應的Mapper接口類文件 </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">javaClientGenerator </span><span style="color: #ff0000">type</span><span style="color: #0000ff">="XMLMAPPER"</span><span style="color: #ff0000"> targetPackage</span><span style="color: #0000ff">="com.yyc.dao"</span><span style="color: #ff0000"> targetProject</span><span style="color: #0000ff">="./src/main/java"</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="enableSubPackages"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span><span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">javaClientGenerator</span><span style="color: #0000ff">&gt;</span> </br></br>   


    <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 列出要生成代碼的所有表，這里配置的是不生成Example文件 </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">table </span><span style="color: #ff0000">tableName</span><span style="color: #0000ff">="user_t"</span><span style="color: #ff0000"> domainObjectName</span><span style="color: #0000ff">="UserInfo"</span><span style="color: #ff0000">    </br>
           enableCountByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000"> enableUpdateByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000"> enableDeleteByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000">    </br>
           enableSelectByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000"> selectByExampleQueryId</span><span style="color: #0000ff">="false"</span> <span style="color: #0000ff">&gt;</span>    
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="useActualColumnNames"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="false"</span><span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">table</span><span style="color: #0000ff">&gt;</span>    </br>
<span style="color: #0000ff">&lt;/</span><span style="color: #800000">context</span><span style="color: #0000ff">&gt;</span>    </br>

</generatorConfiguration>

　　由於上面的文件中使用了數據庫連接，所以還別忘了數據庫的包（相信在准備好學習mybatis前，已經在pom.xml文件中准備好了這些相關依賴）

　　jdbc.properties:　

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc:mysql://localhost:3306/ssm?useUnicode=true&characterEncoding=utf8

jdbc.username=root

jdbc.password=123

#定義初始連接數  

initialSize=0  

#定義最大連接數  

maxActive=20  

#定義最大空閑  

maxIdle=20  

#定義最小空閑  

minIdle=1  

#定義最長等待時間  

maxWait=60000 

　　3.寫GenMain.java main方法

/**
 * 
 */
package main;


import java.io.File;

 import java.io.IOException;

 import java.sql.SQLException;

 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.InvalidConfigurationException;

 import org.mybatis.generator.exception.XMLParserException;

 import org.mybatis.generator.internal.DefaultShellCallback;


/**********************************


    
    
    
            
 
             
@author E-mail:34782655@qq.com
 
             
@version 創建時間：2017年6月23日 下午9:18:19
 
             
類說明:
 
             
 
mybatis逆向工程main函數</br>
 
 
            
**************************************

 /


public class GenMain {

 public static void main(String[] args) { 

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

 boolean overwrite = true;
　　　　　//如果這里出現空指針，直接寫絕對路徑即可。

 String genCfg = "/mbgConfiguration.xml"; 

 File configFile = new File(GenMain.class.getResource(genCfg).getFile()); 

 ConfigurationParser cp = new ConfigurationParser(warnings); 

 Configuration config = null; 

 try { 

 config = cp.parseConfiguration(configFile); 

 } catch (IOException e) { 

 e.printStackTrace(); 

 } catch (XMLParserException e) { 

 e.printStackTrace(); 

 } 

 DefaultShellCallback callback = new DefaultShellCallback(overwrite); 

 MyBatisGenerator myBatisGenerator = null; 

 try { 

 myBatisGenerator = new MyBatisGenerator(config, callback, warnings); 

 } catch (InvalidConfigurationException e) { 

 e.printStackTrace(); 

 } 

 try { 

 myBatisGenerator.generate(null); 

 } catch (SQLException e) { 

 e.printStackTrace(); 

 } catch (IOException e) { 

 e.printStackTrace(); 

 } catch (InterruptedException e) { 

 e.printStackTrace(); 

 } 

 }

 }

　　4、運行Main方法，刷新項目，就會在上面mbgConfiguration.xml中配置的對應文件的目錄下生成實體，mapper,dao了。

第二種方式：maven插件運行

　　1.pom.xml配置插件

　　2.寫generatorConfig.xml文件

　　3.運行

具體步驟：　　

　　1.pom.xml配置插件build節點下加入插件：也就是maven一般加入tomcat插件的地方。

<!-- 第二種方式數據庫反向生成java -->

<plugin> 

<groupId>org.mybatis.generator</groupId> 

<artifactId>mybatis-generator-maven-plugin</artifactId> 

<version>1.3.2</version> 
<configuration> 

<verbose>true</verbose> 
<overwrite>true</overwrite> 
</configuration> 

</plugin>

　　2.寫generatorConfig.xml文件，與mbgConfiguration.xml文件不同的是：文件名固定只能是generatorConfig，文件中要配置數據庫連接驅動絕對路徑，並且，數據庫連接信息url,username,password等都要寫固定<classPathEntry location="E:\MavenRepository\mysql\mysql-connector-java\5.1.38\mysql-connector-java-5.1.38.jar" />

　　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">    

<!-- 第二種mybatis逆向生成xml配置 -->    

<generatorConfiguration>  

<!-- 需要指明數據庫連接器的絕對路徑 -->

    <classPathEntry  

        location="E:\MavenRepository\mysql\mysql-connector-java\5.1.38\mysql-connector-java-5.1.38.jar" />     

    <context id="sqlserverTables" targetRuntime="MyBatis3">    

        <!-- 生成的pojo，將implements Serializable-->    

        <plugin type="org.mybatis.generator.plugins.SerializablePlugin"></plugin>    

        <commentGenerator>    

            <!-- 是否去除自動生成的注釋 true：是 ： false:否 -->    

            <property name="suppressAllComments" value="true" />    

        </commentGenerator> 

   
    <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 數據庫鏈接URL、用戶名、密碼 </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">jdbcConnection </span><span style="color: #ff0000">driverClass</span><span style="color: #0000ff">="com.mysql.jdbc.Driver"</span><span style="color: #ff0000">    </br>
                    connectionURL</span><span style="color: #0000ff">="jdbc:mysql://localhost:3306/ssm"</span><span style="color: #ff0000">    </br>
                    userId</span><span style="color: #0000ff">="root"</span><span style="color: #ff0000">    </br>
                    password</span><span style="color: #0000ff">="123cy-coo.com"</span><span style="color: #0000ff">&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">jdbcConnection</span><span style="color: #0000ff">&gt;</span></br></br>    

    <span style="color: #008000">&lt;!--</span><span style="color: #008000">      </br>
    默認false，把JDBC DECIMAL 和 NUMERIC 類型解析為 Integer    </br>
        true，把JDBC DECIMAL 和 NUMERIC 類型解析為java.math.BigDecimal   </br>   
    </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">javaTypeResolver</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="forceBigDecimals"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="false"</span> <span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">javaTypeResolver</span><span style="color: #0000ff">&gt;</span>    </br></br>

    <span style="color: #008000">&lt;!--</span><span style="color: #008000">     </br>
    生成model模型，對應的包路徑，以及文件存放路徑(targetProject)，targetProject可以指定具體的路徑,如./src/main/java， </br>   
    也可以使用“MAVEN”來自動生成，這樣生成的代碼會在target/generatord-source目錄下    </br>
    </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #008000">&lt;!--</span><span style="color: #008000">&lt;javaModelGenerator targetPackage="com.joey.mybaties.test.pojo" targetProject="MAVEN"&gt;</span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">javaModelGenerator </span><span style="color: #ff0000">targetPackage</span><span style="color: #0000ff">="com.yyc.entity"</span><span style="color: #ff0000"> targetProject</span><span style="color: #0000ff">="./src/main/java"</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="enableSubPackages"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span><span style="color: #0000ff">/&gt;</span>    </br>
        <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 從數據庫返回的值被清理前后的空格  </span><span style="color: #008000">--&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="trimStrings"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span> <span style="color: #0000ff">/&gt;</span>  </br>  
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">javaModelGenerator</span><span style="color: #0000ff">&gt;</span>    </br></br>

    <span style="color: #008000">&lt;!--</span><span style="color: #008000">對應的mapper.xml文件  </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">sqlMapGenerator </span><span style="color: #ff0000">targetPackage</span><span style="color: #0000ff">="mappers"</span><span style="color: #ff0000"> targetProject</span><span style="color: #0000ff">="./src/main/resources"</span><span style="color: #0000ff">&gt;</span>    </br>
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="enableSubPackages"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span><span style="color: #0000ff">/&gt;</span>    
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">sqlMapGenerator</span><span style="color: #0000ff">&gt;</span>    </br></br>

    <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 對應的Mapper接口類文件 </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">javaClientGenerator </span><span style="color: #ff0000">type</span><span style="color: #0000ff">="XMLMAPPER"</span><span style="color: #ff0000"> targetPackage</span><span style="color: #0000ff">="com.yyc.dao"</span><span style="color: #ff0000"> targetProject</span><span style="color: #0000ff">="./src/main/java"</span><span style="color: #0000ff">&gt;</span>    
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="enableSubPackages"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="true"</span><span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">javaClientGenerator</span><span style="color: #0000ff">&gt;</span>    </br></br>


    <span style="color: #008000">&lt;!--</span><span style="color: #008000"> 列出要生成代碼的所有表，這里配置的是不生成Example文件 </span><span style="color: #008000">--&gt;</span>    </br>
    <span style="color: #0000ff">&lt;</span><span style="color: #800000">table </span><span style="color: #ff0000">tableName</span><span style="color: #0000ff">="user_t"</span><span style="color: #ff0000"> domainObjectName</span><span style="color: #0000ff">="UserInfo"</span><span style="color: #ff0000">    </br>
           enableCountByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000"> enableUpdateByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000"> enableDeleteByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000">    </br>
           enableSelectByExample</span><span style="color: #0000ff">="false"</span><span style="color: #ff0000"> selectByExampleQueryId</span><span style="color: #0000ff">="false"</span> <span style="color: #0000ff">&gt;</span>    
        <span style="color: #0000ff">&lt;</span><span style="color: #800000">property </span><span style="color: #ff0000">name</span><span style="color: #0000ff">="useActualColumnNames"</span><span style="color: #ff0000"> value</span><span style="color: #0000ff">="false"</span><span style="color: #0000ff">/&gt;</span>    </br>
    <span style="color: #0000ff">&lt;/</span><span style="color: #800000">table</span><span style="color: #0000ff">&gt;</span></br>    
<span style="color: #0000ff">&lt;/</span><span style="color: #800000">context</span><span style="color: #0000ff">&gt;</span> </br>   

</generatorConfiguration>

　　 3.運行方法：在eclipse 中，選擇pom.xml文件，擊右鍵先擇Run AS——>Maven Build… ——>在Goals框中輸入：mybatis-generator:generate  運行即可。

因為第一種xml文件的配置比較靈活，不像第二種xml中還需要寫死數據庫驅動地址和連接信息，並且還要多加一個jar插件。所以推薦第一種方式