JavaSEリフレクション-コンストラクターを呼び出してオブジェクトをインスタンス化します

コンストラクターを呼び出して、オブジェクトをインスタンス化します

public class User {
    
    

	public int id;
	
	private String name;
	
	String address;
	
	protected int sno;
	
	public User() {
    
    }
	
	public User(int id, String name, String address, int sno) {
    
    
		super();
		this.id = id;
		this.name = name;
		this.address = address;
		this.sno = sno;
	}
	
	public void study() {
    
    
		System.out.println("study...");
	}
	
	public void eat(int a,String b) {
    
    
		System.out.println("eat...");
	}

	@Override
	public String toString() {
    
    
		return "User [id=" + id + ", name=" + name + ", address=" + address + ", sno=" + sno + "]";
	}

	@Override
	public int hashCode() {
    
    
		final int prime = 31;
		int result = 1;
		result = prime * result + ((address == null) ? 0 : address.hashCode());
		result = prime * result + id;
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		result = prime * result + sno;
		return result;
	}

	@Override
	public boolean equals(Object obj) {
    
    
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		User other = (User) obj;
		if (address == null) {
    
    
			if (other.address != null)
				return false;
		} else if (!address.equals(other.address))
			return false;
		if (id != other.id)
			return false;
		if (name == null) {
    
    
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		if (sno != other.sno)
			return false;
		return true;
	}
}

import java.lang.reflect.Constructor;

public class Test {
    
    
	public static void main(String[] args) throws Exception {
    
    
		
		// 调用无参构造方法(一)
		Class userClass = Class.forName("com.lzj.reflect.pojo.User");
		Object object = userClass.newInstance(); // JDK9过时
		System.out.println(object);
		
		// 调用无参构造方法(二)
		Constructor constructor = userClass.getConstructor();
		Object object2 = constructor.newInstance();
		System.out.println(object2);
		
		// 调用有参构造方法
		Constructor constructor2 = userClass.getConstructor(int.class,String.class,String.class,int.class);
		Object object3 = constructor2.newInstance(1,"lzj","diqiu",100);
		System.out.println(object3);
	}
}