public class TestClass {

    public String classInfo;

    public String getClassInfo() {

        return classInfo;

    }

    public TestClass(String classInfo) {

        this.classInfo = classInfo;

        System.out.println("invoke this param classInfo constructor.");

    }

    public TestClass()

    {

        System.out.println("invoke this default constructor.");

    }

    public void setClassInfo(String classInfo) {

        this.classInfo = classInfo;

    }

    static {

        System.out.println("init first class.");

    }

    public void showinfo()

    {

        System.out.println("this is default show info method.");

    }

    public void showinfo(String info)

    {

        System.out.println("this is have param method.");

        System.out.println("param context:"+info);

    }

}

import org.junit.Test;

import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

public class getClassInfoTest {

    @Test

    public void testDemo() throws Exception

    {

        /**

         * 1.实现反射的第一步：获取对象的类型信息，java中指存放类型信息的.class文件

         * 2.在这里是获取对象的所有构造方法.

         * 3.找到需要的构造方法.

         * 4.调用指定构造方法,创建对象.

         */

        Class clazz=Class.forName("TestClass");

        /**

         * 获取构造方法

         * 调用newInstance(...) 相当于 new TestClass(...)

         */

        Constructor[] constructors=clazz.getConstructors();

        System.out.println("constructor item:"+'\n');

        arrayToStringItem(constructors);

        Object test=constructors[0].newInstance();

        Object test2=constructors[1].newInstance("hello");

        /**

         * 获取属性

         */

        Field[] fields=clazz.getFields();

        System.out.println("field item:"+'\n');

        arrayToStringItem(fields);

        Field field=fields[0];

        System.out.println("field name:"+field.getName());

        System.out.println("get dafault constructor field value:"+field.get(test));

        System.out.println("get have param constructor field value:"+field.get(test2));

        /**

         * 获取方法

         */

        Method[] methods=clazz.getMethods();

        System.out.println("method item:"+'\n');

        arrayToStringItem(methods);

        System.out.println("invoke "+methods[0].getName()+" get return value:"+methods[0].invoke(test2));

    }

    public void arrayToStringItem(Object[] args)

    {

        for (Object c:args)

        {

            System.out.println(c);

        }

    }

}