mybatis根據數據庫表結構自動生成實體類，dao，mapper

首先， pom須要引入

<!-- mysql -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.39</version>
    </dependency>
<!-- mybatis-->
 <dependency>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-core</artifactId>
        <version>1.3.3</version>
    </dependency>

而後是mybatis生成器

import org.mybatis.generator.api.CommentGenerator; import org.mybatis.generator.api.IntrospectedColumn; import org.mybatis.generator.api.IntrospectedTable; import org.mybatis.generator.api.dom.java.*; import org.mybatis.generator.api.dom.xml.XmlElement; import org.mybatis.generator.config.MergeConstants; import org.mybatis.generator.config.PropertyRegistry; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Properties; import static org.mybatis.generator.internal.util.StringUtility.isTrue; /** * Mybatis 註釋生成器 */
public class MyCommentGenerator implements CommentGenerator { private Properties properties; private Properties systemPro; private boolean suppressDate; private boolean suppressAllComments; private String currentDateStr; public MyCommentGenerator() { super(); properties = new Properties(); systemPro = System.getProperties(); suppressDate = false; suppressAllComments = false; currentDateStr = (new SimpleDateFormat("yyyy-MM-dd")).format(new Date()); } public void addJavaFileComment(CompilationUnit compilationUnit) { // add no file level comments by default
        return; } /** * Adds a suitable comment to warn users that the element was generated, and * when it was generated. */
    public void addComment(XmlElement xmlElement) { return; } public void addRootComment(XmlElement rootElement) { // add no document level comments by default
        return; } public void addConfigurationProperties(Properties properties) { this.properties.putAll(properties); suppressDate = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_DATE)); suppressAllComments = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_ALL_COMMENTS)); } /** * This method adds the custom javadoc tag for. You may do nothing if you do * not wish to include the Javadoc tag - however, if you do not include the * Javadoc tag then the Java merge capability of the eclipse plugin will * break. * * @param javaElement the java element */
    protected void addJavadocTag(JavaElement javaElement, boolean markAsDoNotDelete) { javaElement.addJavaDocLine(" *"); StringBuilder sb = new StringBuilder(); sb.append(" * "); sb.append(MergeConstants.NEW_ELEMENT_TAG); if (markAsDoNotDelete) { sb.append(" do_not_delete_during_merge"); } String s = getDateString(); if (s != null) { sb.append(' '); sb.append(s); } javaElement.addJavaDocLine(sb.toString()); } /** * This method returns a formated date string to include in the Javadoc tag * and XML comments. You may return null if you do not want the date in * these documentation elements. * * @return a string representing the current timestamp, or null */
    protected String getDateString() { String result = null; if (!suppressDate) { result = currentDateStr; } return result; } public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable) { if (suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); innerClass.addJavaDocLine("/**"); sb.append(" * "); sb.append(introspectedTable.getFullyQualifiedTable()); sb.append(" "); sb.append(getDateString()); innerClass.addJavaDocLine(sb.toString()); innerClass.addJavaDocLine(" */"); } public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable) { if (suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); innerEnum.addJavaDocLine("/**"); 
        sb.append(" * "); sb.append(introspectedTable.getFullyQualifiedTable()); innerEnum.addJavaDocLine(sb.toString()); innerEnum.addJavaDocLine(" */"); } public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) { if (suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); field.addJavaDocLine("/**"); sb.append(" * "); sb.append(introspectedColumn.getRemarks()); field.addJavaDocLine(sb.toString()); // addJavadocTag(field, false);
 field.addJavaDocLine(" */"); } public void addFieldComment(Field field, IntrospectedTable introspectedTable) { if (suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); field.addJavaDocLine("/**"); sb.append(" * "); sb.append(introspectedTable.getFullyQualifiedTable()); field.addJavaDocLine(sb.toString()); field.addJavaDocLine(" */"); } public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { } public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable) { if (suppressAllComments) { return; } 
 } public void addGetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) { if (suppressAllComments) { return; } method.addJavaDocLine("/**"); StringBuilder sb = new StringBuilder(); sb.append(" * "); sb.append(introspectedColumn.getRemarks()); method.addJavaDocLine(sb.toString()); sb.setLength(0); sb.append(" * @return "); sb.append(introspectedColumn.getActualColumnName()); sb.append(" "); sb.append(introspectedColumn.getRemarks()); method.addJavaDocLine(sb.toString()); // addJavadocTag(method, false);
 method.addJavaDocLine(" */"); } public void addSetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) { if (suppressAllComments) { return; } method.addJavaDocLine("/**"); StringBuilder sb = new StringBuilder(); sb.append(" * "); sb.append(introspectedColumn.getRemarks()); method.addJavaDocLine(sb.toString()); Parameter parm = method.getParameters().get(0); sb.setLength(0); sb.append(" * @param "); sb.append(parm.getName()); sb.append(" "); sb.append(introspectedColumn.getRemarks()); method.addJavaDocLine(sb.toString()); // addJavadocTag(method, false);
 method.addJavaDocLine(" */"); } public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete) { if (suppressAllComments) { return; } StringBuilder sb = new StringBuilder(); innerClass.addJavaDocLine("/**"); sb.append(" * "); sb.append(introspectedTable.getFullyQualifiedTable()); innerClass.addJavaDocLine(sb.toString()); sb.setLength(0); sb.append(" * @author "); sb.append(systemPro.getProperty("user.name")); sb.append(" "); sb.append(currentDateStr); // addJavadocTag(innerClass, markAsDoNotDelete);
 innerClass.addJavaDocLine(" */"); } }

 

而後是generator.xml 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="my" targetRuntime="MyBatis3">

<!-- 這裏的type裏寫的是你的實現類的類全路徑，即上面那個生成器所在的位置 -->
        <commentGenerator type="org.mybatis.generator.MyCommentGenerator">
        </commentGenerator>
        <!--鏈接數據庫 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://遠程地址:3306/數據庫名" userId="數據庫用戶名" password="密碼"/>                                                             
        <!-- 實體類的地址 targetProject + targetPackage == 生成文件所在位置 根據表結構生成的實體類就在項目的com.common.model中-->
        <javaModelGenerator targetPackage="com.common.model" targetProject="E:\common\src\main\java">                   
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <!-- mapper文件地址 targetProject + targetPackage == 生成文件所在物理位置 生成的.mapper文件就在mybatis文件夾下-->
        <sqlMapGenerator targetPackage="mybatis" targetProject="E:\src\main\resources">
            <property name="enableSubPackages" value="true"/>                                          
        </sqlMapGenerator>
        <!-- dao生成的存放地址 targetProject + targetPackage == 生成文件所在位置 生成的dao接口就在項目的com.dao中-->
        <javaClientGenerator targetPackage="com.dao" targetProject="E:\src\main\java" type="XMLMAPPER">
            <property name="enableSubPackages" value="true"/>                                            
        </javaClientGenerator>
        <!-- tableName 數據庫中表的名字 domainObjectName 生成的實體類名字以及加上Dao和Mapper組成的dao和mapper文件的名字 -->
        <table tableName="數據庫表的名字" domainObjectName="生成實體類的名字" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false">
            <property name="useActualColumnNames" value="true"/>
        </table>

        
    </context>
</generatorConfiguration>

最後是要執行的的類，執行這個類， 就能生成相應的文件了， 執行完可能須要更新下項目才能看出效果

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; import java.io.File; import java.io.IOException; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; 
public class MyBatisGeneratorTest { public static void main(String[] args) { try { List<String> warnings = new ArrayList<String>(); boolean overwrite = true; 
             File configFile = new File("E:\\src\\main\\resource\\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); } catch (SQLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } catch (InvalidConfigurationException e) { e.printStackTrace(); } catch (XMLParserException e) { e.printStackTrace(); } } }