Java 反射

一个小小的Demo, 对Class不理解的去看看慕课网的反射

package com.reflect;

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

public class Test {
    /**
     * Class 所有类的类类型
     * getMethods 取public方法
     * getDeclaredMethods() 取自身的所有方法包括(private 等)
     * @param args
     */
    public static void main(String[] args) {
        Class c = Student.class;
        
        //构造函数
        Constructor [] cons = c.getConstructors();
        for (Constructor constructor : cons) {
            Class[] params = constructor.getParameterTypes();
            System.out.print(constructor.getName()+"(");
            for (int i = 0; i < params.length; i++) {
                System.out.print(params[i].getName()+",");
            }
            System.out.println(")");
        }
        System.out.println("===================================");
        
        //方法
        Method[] m  = c.getMethods();
        for (Method method : m) {
            Class[] params = method.getParameterTypes();
            System.out.print(method.getReturnType().getName() + " " +method.getName()+"(");
            for (int i = 0; i < params.length; i++) {
                System.out.print(params[i].getName()+",");
            }
            System.out.println(")");
        }
        System.out.println("===================================");
        
        //字段
        Field[] f = c.getDeclaredFields();
        for (Field field : f) {
            System.out.println(field.getType().getName() + " " +field.getName());
        }
        
        try {
            //单个方法的调用
            Student s = new Student();
            Method method = c.getMethod("sayHello", new Class[]{});
            method.invoke(s);
            
            //单个字段的取值
            请看下面的Field使用,个人觉得写的不错
        } catch (Exception e) {
            e.printStackTrace();
        } 
    }
}

 

 

 

 

package com.reflect;

public class Student {
    private String  name;
    private Integer age;
    
    public Student(){}
    public Student(String name, Integer age){
        this.name = name;
        this.age = age;
    }
    
    public void sayHello(){
        System.out.println("hello.");
    }
    
    private void sayGood(){
        System.out.println("good.");
    }
    
    
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    
    
    
}

Field 使用: 转载 http://www.cnblogs.com/manuosex/p/3852716.html