Mybatis generator
其主要的功能就是方便，快捷的创建好Dao，entry，xml 加快了开发速度，使用方面根据其提供的规则配置好就OK
这里还有一个重要的开发场景，开发过程中，对数据库的操作肯定很多，比如新增字段什么的，你只要将原先自动生成的一套代码删除，重新再生成一份，这就完美解决了，但是这样做的前提是，你必须对生成后的代码不改动，只是使用。不需要想手动开发写代码那样到处改代码，还担心改漏地方。
其实这个的实现方式也是五花八门的，写一种比较常见的
主要流程
第一步：添加依赖
主要是jdbc和generator
<!-- https://mvnrepository.com/artifact/org.mybatis.generator/mybatis-generator-core --> <dependency> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator-core</artifactId> <version>1.3.6</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.38</version> </dependency>
第二步：配置 generatorConfig.xml
这个文件主要是对 从哪来，到哪去的描述，还有一些特殊要求的配置
<?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="DB2Tables" targetRuntime="MyBatis3"> <!-- 生成mysql带有分页的sql的插件 这个可以自己写，--> <plugin type="generator.MysqlPaginationPlugin" /> <plugin type="org.mybatis.generator.plugins.ToStringPlugin" /> <plugin type="org.mybatis.generator.plugins.SerializablePlugin" /> <!-- 自定义的注释规则，继承 DefaultCommentGenerator 重写 一些方法 --> <commentGenerator type="generator.NewbatisGenerator"> <!-- 是否去除自动生成日期的注释 true：是 ： false:否 --> <property name="suppressDate" value="true"/> <!-- 是否去除所有自动生成的注释 true：是 ： false:否 --> <property name="suppressAllComments" value="true"/> </commentGenerator> <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://数据库地址" userId="username" password="password"> </jdbcConnection> <!--生成entity类存放位置--> <javaModelGenerator targetPackage="包名（com.generator.test.entity）" targetProject="项目地址到\java （D:\workspace\src\main\java）"> <property name="enableSubPackages" value="true"/> <property name="trimStrings" value="true"/> </javaModelGenerator> <!--生成映射文件存放位置--> <sqlMapGenerator targetPackage="包名（com.generator.test.mapper）" targetProject="项目地址到\java （D:\workspace\src\main\java）"> <property name="enableSubPackages" value="true"/> </sqlMapGenerator> <!--生成Dao类存放位置--> <javaClientGenerator type="XMLMAPPER" targetPackage="包名（com.generator.test.dao）" targetProject="项目地址到\java （D:\workspace\src\main\java）"> <property name="enableSubPackages" value="true"/> </javaClientGenerator> <table tableName="表名" domainObjectName="生成实体的类名"> </table> </context> </generatorConfiguration>
第三步：主要看你个人的需求，对注释，分页啥的有啥要求不，可以重写几个方法对其进行改造
主要举几个例子
对注释的修改 NewbatisGenerator
public class NewbatisGenerator extends DefaultCommentGenerator { private Properties properties; private Properties systemPro; private boolean suppressDate; private boolean suppressAllComments; private String currentDateStr; public NewbatisGenerator() { super(); properties = new Properties(); systemPro = System.getProperties(); suppressDate = false; suppressAllComments = false; currentDateStr = (new SimpleDateFormat("yyyy-MM-dd")).format(new Date()); } /** * 对类的注解 * @param topLevelClass * @param introspectedTable */ @Override public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { topLevelClass.addJavaDocLine("/**"); topLevelClass.addJavaDocLine(" * 这是MyBatis Generator自动生成的Model Class."); StringBuilder sb = new StringBuilder(); sb.append(" * 对应的数据表是 : "); sb.append(introspectedTable.getFullyQualifiedTable()); topLevelClass.addJavaDocLine(sb.toString()); String tableRemarks = introspectedTable.getRemarks(); if (!StringUtils.isEmpty(tableRemarks)) { sb.setLength(0); sb.append(" * 数据表注释 : "); sb.append(tableRemarks); topLevelClass.addJavaDocLine(sb.toString()); } sb.setLength(0); sb.append(" * @author "); sb.append(systemPro.getProperty("user.name")); topLevelClass.addJavaDocLine(sb.toString()); String curDateString = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")).format(new Date()); sb.setLength(0); sb.append(" * @date "); sb.append(curDateString); topLevelClass.addJavaDocLine(sb.toString()); topLevelClass.addJavaDocLine(" */"); } /** * 生成的实体增加字段的中文注释 */ 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().replace("\n", " ")); field.addJavaDocLine(" */"); } }
对分页的添加 MysqlPaginationPlugin 自动生成带分页插件
public class MysqlPaginationPlugin extends PluginAdapter { public MysqlPaginationPlugin() {} public boolean modelExampleClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) { this.addLimit(topLevelClass, introspectedTable, "limitStart"); this.addLimit(topLevelClass, introspectedTable, "limitSize"); return super.modelExampleClassGenerated(topLevelClass, introspectedTable); } public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable) { XmlElement isNotNullElement = new XmlElement("if"); isNotNullElement .addAttribute(new Attribute("test", "limitStart != null and limitSize >= 0")); isNotNullElement.addElement(new TextElement("limit #{limitStart} , #{limitSize}")); element.addElement(isNotNullElement); return super.sqlMapSelectByExampleWithoutBLOBsElementGenerated(element, introspectedTable); } public boolean sqlMapSelectByExampleWithBLOBsElementGenerated(XmlElement element, IntrospectedTable introspectedTable) { XmlElement isNotNullElement = new XmlElement("if"); isNotNullElement .addAttribute(new Attribute("test", "limitStart != null and limitSize >= 0")); isNotNullElement.addElement(new TextElement("limit #{limitStart} , #{limitSize}")); element.addElement(isNotNullElement); return super.sqlMapSelectByExampleWithBLOBsElementGenerated(element, introspectedTable); } private void addLimit(TopLevelClass topLevelClass, IntrospectedTable introspectedTable, String name) { CommentGenerator commentGenerator = this.context.getCommentGenerator(); Field field = new Field(); field.setVisibility(JavaVisibility.PROTECTED); field.setType(PrimitiveTypeWrapper.getIntegerInstance()); field.setName(name); commentGenerator.addFieldComment(field, introspectedTable); topLevelClass.addField(field); char c = name.charAt(0); String camel = Character.toUpperCase(c) + name.substring(1); Method method = new Method(); method.setVisibility(JavaVisibility.PUBLIC); method.setName("set" + camel); method.addParameter(new Parameter(PrimitiveTypeWrapper.getIntegerInstance(), name)); StringBuilder sb = new StringBuilder(); sb.append("this."); sb.append(name); sb.append(" = "); sb.append(name); sb.append(";"); method.addBodyLine(sb.toString()); commentGenerator.addGeneralMethodComment(method, introspectedTable); topLevelClass.addMethod(method); Method getterMethod = AbstractJavaGenerator.getGetter(field); commentGenerator.addGeneralMethodComment(getterMethod, introspectedTable); topLevelClass.addMethod(getterMethod); } public boolean validate(List<String> warnings) { return true; } /** * 生成mapper.xml,文件内容会被清空再写入 * */ @Override public boolean sqlMapGenerated(GeneratedXmlFile sqlMap, IntrospectedTable introspectedTable) { sqlMap.setMergeable(false); return super.sqlMapGenerated(sqlMap, introspectedTable); } }
最后一步：运行生成
这些官网都是有的
public class Generator { public static void main(String[] args) throws Exception{ List<String> warnings = new ArrayList<String>(); boolean overwrite = true; File configFile = new File("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); } }
这个比较简单明了，个性化也不错，值得推荐
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