Mybatis实现接口自动生成实现类对接口中抽象方法的重写-----Mybatis框架

Bertha 。 2024-03-08 01:54 80阅读 0赞

>     package com.powernode.javassist;
>     
>     import com.powernode.bank.dao.AccountDao;
>     import javassist.ClassPool;
>     import javassist.CtClass;
>     import javassist.CtMethod;
>     import org.junit.Test;
>     
>     import java.lang.reflect.Constructor;
>     import java.lang.reflect.Method;
>     import java.util.Arrays;
>     
>     public class JavassistTest
>     {
>         @Test
>         public void TestGenerateAccountDaoImpl() throws Exception
>         {
>             //获取类池
>             ClassPool pool = ClassPool.getDefault();
>             //制造类
>             CtClass ctClass = pool.makeClass("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //制造接口
>             CtClass Interface = pool.makeInterface("com.powernode.bank.dao.AccountDao");
>             //实现接口
>             ctClass.addInterface(Interface);
>             //获取所有的方法,获取接口中所有的方法
>             Method[] methods = AccountDao.class.getDeclaredMethods();
>             Arrays.stream(methods).forEach(method ->
>             {
>                 //method是接口的抽象方法,我们现在需要实现这些方法
>                 try
>                 {
>                     //"public void insert(){System.out.println(123);}"我们要拼接出来的结果
>                     StringBuilder methodCode = new StringBuilder();
>                     methodCode.append("public ");//追加修饰符列表
>                     methodCode.append(method.getReturnType().getName());//最佳返回值类型
>                     methodCode.append(" ");
>                     methodCode.append(method.getName());//追加方法名字
>                     methodCode.append("(");
>                     //拼接参数,并用逗号隔开
>                     Class<?>[] parameterTypes = method.getParameterTypes();
>                     for (int i = 0; i < parameterTypes.length; i++)
>                     {
>                         Class<?> parameterType = parameterTypes[i];
>                         methodCode.append(parameterType.getName());
>                         methodCode.append(" ");
>     //                    methodCode.append(parameterType.getName().toLowerCase().charAt(0) + parameterType.getName().substring(1));
>                         methodCode.append("arg" + i);
>                         if(i != parameterTypes.length - 1)
>                         {
>                             methodCode.append(",");
>                         }
>                     }
>                     methodCode.append("){");
>                     methodCode.append("System.out.println(123);");
>                     //添加Return语句
>                     String simpleName = method.getReturnType().getSimpleName();
>                     if("void".equals(simpleName)) {}
>                     else if("int".equals(simpleName))
>                     {
>                         methodCode.append("return 1;");
>                     }
>                     else if("String".equals(simpleName))
>                     {
>                         methodCode.append("return \"hello\";");
>                     }
>                     else if("double".equals(simpleName))
>                     {
>                         methodCode.append("return 1;");
>                     }
>                     methodCode.append("}");
>                     System.out.println(methodCode);
>                     CtMethod ctMethod = CtMethod.make(methodCode.toString(),ctClass);
>                     ctClass.addMethod(ctMethod);
>                 }
>                 catch (Exception e)
>                 {
>                     e.printStackTrace();
>                 }
>             });
>             //实现接口中所有的方法
>             //在内存中生成class,并加载到JVM中
>             Class<?> aClass = ctClass.toClass();
>     //        //创建对象
>             Constructor<?> declaredConstructor = aClass.getDeclaredConstructor();
>             AccountDao accountDao = (AccountDao) declaredConstructor.newInstance();
>             //调用方法
>             accountDao.insert("aaaa");
>             accountDao.update("aaaa",1000.0);
>             accountDao.selectByActno("aaaa");
>             accountDao.delete();
>         }
>         @Test
>         public void TestGenerateFirstClass() throws Exception
>         {
>             //获取类池,用于生成Class
>             ClassPool pool = ClassPool.getDefault();
>             //需要完整全类名
>             CtClass ctClass = pool.makeClass("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //制造方法
>             String methodCode = "public void insert(){System.out.println(123);}";
>             CtMethod ctMethod = CtMethod.make(methodCode,ctClass);
>             //将方法添加到类中
>             ctClass.addMethod(ctMethod);
>             //生成类(在内存中生成class)
>             ctClass.toClass();
>             //类加载返回AccountDaoImpl的字节码
>             //这里内存里就有这个类了,所以可以使用Class.forName创建class对象
>             Class<?> aClass = Class.forName("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //创建对象
>             Constructor<?> declaredConstructor = aClass.getDeclaredConstructor();
>             Object o = declaredConstructor.newInstance();
>             //获取AccountDaoImpl的Insert方法
>             Method insert = aClass.getDeclaredMethod("insert");
>             insert.invoke(o);
>         }
>         @Test
>         public void TestGenerateImpl() throws Exception
>         {
>             //获取类池
>             ClassPool pool = ClassPool.getDefault();
>             //制造类
>             CtClass ctClass = pool.makeClass("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //制造接口
>             CtClass ctInterface = pool.makeInterface("com.powernode.bank.dao.AccountDao");
>             //添加接口到类中
>             ctClass.addInterface(ctInterface);//相当于AccountDaoImpl去implements接口AccountDao
>             //实现接口的方法(制造方法先)
>             //制造方法
>             CtMethod ctMethod = CtMethod.make("public void delete(){System.out.println(\"hello delete!\");}", ctClass);
>             ctClass.addMethod(ctMethod);
>             //在内存中生成类(同时将生成的类加载到JVM中)
>             Class<?> aClass = ctClass.toClass();
>             Constructor<?> declaredConstructor = aClass.getDeclaredConstructor();
>             AccountDao accountDao = (AccountDao)declaredConstructor.newInstance();
>             accountDao.delete();
>         }
>     }
> 
>     package com.powernode.javassist;
>     
>     import com.powernode.bank.dao.AccountDao;
>     import javassist.ClassPool;
>     import javassist.CtClass;
>     import javassist.CtMethod;
>     import org.junit.Test;
>     
>     import java.lang.reflect.Constructor;
>     import java.lang.reflect.Method;
>     import java.util.Arrays;
>     
>     public class JavassistTest
>     {
>         @Test
>         public void TestGenerateAccountDaoImpl() throws Exception
>         {
>             //获取类池
>             ClassPool pool = ClassPool.getDefault();
>             //制造类
>             CtClass ctClass = pool.makeClass("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //制造接口
>             CtClass Interface = pool.makeInterface("com.powernode.bank.dao.AccountDao");
>             //实现接口
>             ctClass.addInterface(Interface);
>             //获取所有的方法,获取接口中所有的方法
>             Method[] methods = AccountDao.class.getDeclaredMethods();
>             Arrays.stream(methods).forEach(method ->
>             {
>                 //method是接口的抽象方法,我们现在需要实现这些方法
>                 try
>                 {
>                     //"public void insert(){System.out.println(123);}"我们要拼接出来的结果
>                     StringBuilder methodCode = new StringBuilder();
>                     methodCode.append("public ");//追加修饰符列表
>                     methodCode.append(method.getReturnType().getName());//最佳返回值类型
>                     methodCode.append(" ");
>                     methodCode.append(method.getName());//追加方法名字
>                     methodCode.append("(");
>                     //拼接参数,并用逗号隔开
>                     Class<?>[] parameterTypes = method.getParameterTypes();
>                     for (int i = 0; i < parameterTypes.length; i++)
>                     {
>                         Class<?> parameterType = parameterTypes[i];
>                         methodCode.append(parameterType.getName());
>                         methodCode.append(" ");
>     //                    methodCode.append(parameterType.getName().toLowerCase().charAt(0) + parameterType.getName().substring(1));
>                         methodCode.append("arg" + i);
>                         if(i != parameterTypes.length - 1)
>                         {
>                             methodCode.append(",");
>                         }
>                     }
>                     methodCode.append("){");
>                     methodCode.append("System.out.println(123);");
>                     //添加Return语句
>                     String simpleName = method.getReturnType().getSimpleName();
>                     if("void".equals(simpleName)) {}
>                     else if("int".equals(simpleName))
>                     {
>                         methodCode.append("return 1;");
>                     }
>                     else if("String".equals(simpleName))
>                     {
>                         methodCode.append("return \"hello\";");
>                     }
>                     else if("double".equals(simpleName))
>                     {
>                         methodCode.append("return 1;");
>                     }
>                     methodCode.append("}");
>                     System.out.println(methodCode);
>                     CtMethod ctMethod = CtMethod.make(methodCode.toString(),ctClass);
>                     ctClass.addMethod(ctMethod);
>                 }
>                 catch (Exception e)
>                 {
>                     e.printStackTrace();
>                 }
>             });
>             //实现接口中所有的方法
>             //在内存中生成class,并加载到JVM中
>             Class<?> aClass = ctClass.toClass();
>     //        //创建对象
>             Constructor<?> declaredConstructor = aClass.getDeclaredConstructor();
>             AccountDao accountDao = (AccountDao) declaredConstructor.newInstance();
>             //调用方法
>             accountDao.insert("aaaa");
>             accountDao.update("aaaa",1000.0);
>             accountDao.selectByActno("aaaa");
>             accountDao.delete();
>         }
>         @Test
>         public void TestGenerateFirstClass() throws Exception
>         {
>             //获取类池,用于生成Class
>             ClassPool pool = ClassPool.getDefault();
>             //需要完整全类名
>             CtClass ctClass = pool.makeClass("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //制造方法
>             String methodCode = "public void insert(){System.out.println(123);}";
>             CtMethod ctMethod = CtMethod.make(methodCode,ctClass);
>             //将方法添加到类中
>             ctClass.addMethod(ctMethod);
>             //生成类(在内存中生成class)
>             ctClass.toClass();
>             //类加载返回AccountDaoImpl的字节码
>             //这里内存里就有这个类了,所以可以使用Class.forName创建class对象
>             Class<?> aClass = Class.forName("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //创建对象
>             Constructor<?> declaredConstructor = aClass.getDeclaredConstructor();
>             Object o = declaredConstructor.newInstance();
>             //获取AccountDaoImpl的Insert方法
>             Method insert = aClass.getDeclaredMethod("insert");
>             insert.invoke(o);
>         }
>         @Test
>         public void TestGenerateImpl() throws Exception
>         {
>             //获取类池
>             ClassPool pool = ClassPool.getDefault();
>             //制造类
>             CtClass ctClass = pool.makeClass("com.powernode.bank.dao.impl.AccountDaoImpl");
>             //制造接口
>             CtClass ctInterface = pool.makeInterface("com.powernode.bank.dao.AccountDao");
>             //添加接口到类中
>             ctClass.addInterface(ctInterface);//相当于AccountDaoImpl去implements接口AccountDao
>             //实现接口的方法(制造方法先)
>             //制造方法
>             CtMethod ctMethod = CtMethod.make("public void delete(){System.out.println(\"hello delete!\");}", ctClass);
>             ctClass.addMethod(ctMethod);
>             //在内存中生成类(同时将生成的类加载到JVM中)
>             Class<?> aClass = ctClass.toClass();
>             Constructor<?> declaredConstructor = aClass.getDeclaredConstructor();
>             AccountDao accountDao = (AccountDao)declaredConstructor.newInstance();
>             accountDao.delete();
>         }
>     }

>     package com.powernode.bank.dao;
>     
>     public interface AccountDao
>     {
>         void delete();
>         int insert(String actno);
>         int update(String actno,Double balance);
>         String selectByActno(String actno);
>     }
> 
>     package com.powernode.bank.dao;
>     
>     public interface AccountDao
>     {
>         void delete();
>         int insert(String actno);
>         int update(String actno,Double balance);
>         String selectByActno(String actno);
>     }

>     <?xml version="1.0" encoding="UTF-8"?>
>     <project xmlns="http://maven.apache.org/POM/4.0.0"
>              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
>         <modelVersion>4.0.0</modelVersion>
>     
>         <groupId>com.powernode</groupId>
>         <artifactId>javassist-Test</artifactId>
>         <version>1.0-SNAPSHOT</version>
>         <packaging>jar</packaging>
>         <dependencies>
>             <dependency>
>                 <groupId>org.javassist</groupId>
>                 <artifactId>javassist</artifactId>
>                 <version>3.29.1-GA</version>
>             </dependency>
>             <dependency>
>                 <groupId>junit</groupId>
>                 <artifactId>junit</artifactId>
>                 <version>4.13.2</version>
>                 <scope>test</scope>
>             </dependency>
>         </dependencies>
>         <properties>
>             <maven.compiler.source>17</maven.compiler.source>
>             <maven.compiler.target>17</maven.compiler.target>
>             <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
>         </properties>
>     
>     </project>
> 
>     <?xml version="1.0" encoding="UTF-8"?>
>     <project xmlns="http://maven.apache.org/POM/4.0.0"
>              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
>         <modelVersion>4.0.0</modelVersion>
>     
>         <groupId>com.powernode</groupId>
>         <artifactId>javassist-Test</artifactId>
>         <version>1.0-SNAPSHOT</version>
>         <packaging>jar</packaging>
>         <dependencies>
>             <dependency>
>                 <groupId>org.javassist</groupId>
>                 <artifactId>javassist</artifactId>
>                 <version>3.29.1-GA</version>
>             </dependency>
>             <dependency>
>                 <groupId>junit</groupId>
>                 <artifactId>junit</artifactId>
>                 <version>4.13.2</version>
>                 <scope>test</scope>
>             </dependency>
>         </dependencies>
>         <properties>
>             <maven.compiler.source>17</maven.compiler.source>
>             <maven.compiler.target>17</maven.compiler.target>
>             <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
>         </properties>
>     
>     </project>