Mybatis generator生成工具简单介绍
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);
}
}
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