Java反射获取class对象方式解析

package com.reflection;
 
/**
 * Created by Liuxd on 2018-08-15.
 */
public class User {
  private String name;
  private Integer age;
 
  public User() {
  }
 
  public User(String name, Integer age) {
    this.name = name;
    this.age = age;
  }
 
  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;
  }
 
  @Override
  public String toString() {
    return "User{" +
        "name='" + name + '\'' +
        ", age=" + age +
        '}';
  }
}

package com.reflection;
 
/**
 * Created by Liuxd on 2018-08-15.
 */
public class TestReflection {
 
  public static void main(String[] args) {
//   第一、通过Class.forName方式
    Class clazz1 = null;
    try {
      clazz1 = Class.forName("com.reflection.User");
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
 
//   第二、通过对象实例方法获取对象
    Class clazz2 = User.class;
 
//   第三、通过Object类的getClass方法
    User user = new User();
    Class clazz3 = user.getClass();
 
    System.out.println(clazz1);
    System.out.println(clazz2);
    System.out.println(clazz3);
  }
}

// 调用无参构造器 ，若是没有，则会报异常
Object o = clazz.newInstance();

//获取构造函数类的对象
Constroctor constroctor = clazz.getConstructor(String.class,Integer.class); 
// 使用构造器对象的newInstance方法初始化对象
Object obj = constroctor.newInstance("龙哥", 29); 

package com.reflection;
import java.lang.reflect.Constructor;
/**
 * Created by Liuxd on 2018-08-15.
 */
public class TestReflection {
 
  public static void main(String[] args) {
//   第一、通过Class.forName方式
    Class clazz1 = null;
    try {
      clazz1 = Class.forName("com.reflection.User");
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
 
//   第二、通过对象实例方法获取对象
    Class clazz2 = User.class;
 
//   第三、通过Object类的getClass方法
    User user = new User();
    Class clazz3 = user.getClass();
    System.out.println(clazz1);
    System.out.println(clazz2);
    System.out.println(clazz3);
    User user1 = null;
    try {
       user1 =(User) clazz1.newInstance();
    } catch (InstantiationException e) {
      e.printStackTrace();
    } catch (IllegalAccessException e) {
      e.printStackTrace();
    }
    user1.setName("终结者");
    user1.setAge(1500);
    System.out.println("user1:"+user1.toString());
    User user2 = null;
    try {
      // 获取构造函数
      Constructor constroctor = clazz2.getConstructor(String.class,Integer.class);
      // 通过构造器对象的newInstance方法进行对象的初始化
      user2 = (User) constroctor.newInstance("龙哥",29);
    } catch (Exception e) {
      e.printStackTrace();
    }
    System.out.println("user2:"+user2.toString());
  }
}