mybatis根据数据库表结构自动生成实体类，dao，mapper _数据库表

【mybatis根据数据库表结构自动生成实体类，dao，mapper】知识的领域是无限的,我们的学习也是无限期的。这篇文章主要讲述mybatis根据数据库表结构自动生成实体类，dao，mapper相关的知识，希望能为你提供帮助。
首先， pom需要引入

< !-- 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>

然后是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 注释生成器 */ 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(" */"); } }

然后是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">

< !-- 这里的type里写的是你的实现类的类全路径，即上面那个生成器所在的位置 --> < commentGenerator type="org.mybatis.generator.MyCommentGenerator"> < /commentGenerator> < !--连接数据库 --> < jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://远程地址:3306/数据库名" userId="数据库用户名" password="密码"/> < !-- 实体类的地址 targetProject + targetPackage == 生成文件所在位置根据表结构生成的实体类就在项目的com.common.model中--> < javaModelGenerator targetPackage="com.common.model" targetProject="E:commonsrcmainjava"> < property name="enableSubPackages" value="https://www.songbingjia.com/android/true"/> < property name="trimStrings" value="https://www.songbingjia.com/android/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文件夹下--> < sqlMapGenerator targetPackage="mybatis" targetProject="E:srcmain esources"> < property name="enableSubPackages" value="https://www.songbingjia.com/android/true"/> < /sqlMapGenerator> < !-- dao生成的存放地址 targetProject + targetPackage == 生成文件所在位置生成的dao接口就在项目的com.dao中--> < javaClientGenerator targetPackage="com.dao" targetProject="E:srcmainjava" type="XMLMAPPER"> < property name="enableSubPackages" value="https://www.songbingjia.com/android/true"/> < /javaClientGenerator> < !-- tableName 数据库中表的名字domainObjectName生成的实体类名字以及加上Dao和Mapper组成的dao和mapper文件的名字 --> < table tableName="数据库表的名字" domainObjectName="生成实体类的名字" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"> < property name="useActualColumnNames" value="https://www.songbingjia.com/android/true"/> < /table> < /context> < /generatorConfiguration>

最后是要执行的的类，执行这个类，就能生成相应的文件了，执行完可能需要更新下项目才能看出效果

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(); } }}