javaassist 创建类

创建一个类，测试，

import javassist.CannotCompileException;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.LoaderClassPath;
import javassist.NotFoundException;

// ssist
public class JavaSssistHelloWord {

   public static void main(String[] args) throws NotFoundException, CannotCompileException, InstantiationException, IllegalAccessException {
       ClassPool pool = new ClassPool(true);
       //pool.i
       // 类池插入类路径
       pool.insertClassPath(new LoaderClassPath(JavaSssistHelloWord.class
               .getClassLoader()));
       // 创建类
       CtClass targetClass = pool.makeClass("com.test.hello");
       // 添加接口
       targetClass.addInterface(pool.get(IHello.class.getName()));
       CtClass returnType=pool.get(void.class.getName());
       String mname="sayHello";
       CtClass[] parameters=new CtClass[]{pool.get(String.class.getName())};
       CtMethod method=new CtMethod(returnType, mname, parameters, targetClass);


       String src="{"
               + "System.out.println($1);"
               +"int i=System.nanoTime();"
               +"System.out.println(i);"
               + "System.out.println($args.toString());"
//               + "System.out.println($r+\"\");"
//               + "System.out.println($type.toString())"
//               + "System.out.println($class.toString())"
               + "System.out.println(\"hello \"+$1);"
               + "}";
       method.setBody(src);
       targetClass.addMethod(method);

       Class cla = targetClass.toClass();
       IHello hello = (IHello) cla.newInstance();
       hello.sayHello("try javaassit");

}

   public interface IHello {
       public void sayHello(String name);
   }
}

输出如下:

try javaassit
-1390196567
[Ljava.lang.Object;@3830f1c0
hello try javaassit

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