java反射 实例

package ref;
public class Ref {
    private int age;
    private String name;
    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Ref(){
        age=18;
        name="hans";
    }
    public Ref(String s){
        this.name=s;
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
      Ref testReflect = new Ref();
      final int m=10000;
      byte bytes[];
      while(true){
          bytes=new byte[500*m];  
          bytes=null;
          System.gc();
      }

    }
}

package ref;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

public class reftest {
    //获取类
    public static void main(String[] args) throws ClassNotFoundException {
    Class c1=Class.forName("ref.Ref");
    System.out.println(c1.getName());
    System.out.println("////////////////////////");
    // 实例化
    try {
        Object o1=c1.newInstance();
    } catch (InstantiationException | IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    //获取属性
    Field[] f=c1.getDeclaredFields();
    StringBuffer sb1=new StringBuffer();
    sb1.append(Modifier.toString(c1.getModifiers()) + " class " + c1.getSimpleName() +"{
"); 
    for(Field f1:f){
    sb1.append(Modifier.toString(f1.getModifiers())+" ");
    sb1.append(f1.getType().getSimpleName()+" ");
    sb1.append(f1.getName()+"
");
    }
    System.out.println(sb1+"}");
    
    
    //获取方法
    Method[] m=c1.getDeclaredMethods();
    StringBuffer sb2=new StringBuffer();
    sb2.append(Modifier.toString(c1.getModifiers()) + " class " + c1.getSimpleName() +"{
"); 
    for(Method m1:m){
        sb2.append(Modifier.toString(m1.getModifiers())+" ");
        sb2.append(m1.getReturnType().getSimpleName()+" ");
        sb2.append(m1.getName()+"
");
        }
        System.out.println(sb2+"}");
        
        
    // 获取构造方法
    Constructor[] con=c1.getDeclaredConstructors();
    StringBuffer sb3=new StringBuffer();
    sb3.append(Modifier.toString(c1.getModifiers()) + " class " + c1.getSimpleName() +"{
"); 
    for(Constructor con1:con){
    sb3.append(Modifier.toString(con1.getModifiers())+" ");
        //构造方法没有返回值
        //sb3.append(con1.getReturnType().getSimpleName()+" ");
    sb3.append(con1.getName()+"
");
     }
     System.out.println(sb3+"}");
    
    }
}




结果如下：

ref.Ref
////////////////////////
public class Ref{
private int age
private String name
}
public class Ref{
public int getAge
public void setAge
public static void main
public String getName
public void setName
}
public class Ref{
public ref.Ref
public ref.Ref
}

不足之处

1，方法及构造方法里面的参数类型没有传回来；

2，构造方法前带着包名；