java反射-使用Class对象创建对象

 
public class UserInfo {
 
    private long id;
    private String username;
    private String password;
 
    public UserInfo() {
        System.out.println("public UserInfo()");
    }
 
    public UserInfo(long id) {
        super();
        this.id = id;
    }
 
    public UserInfo(long id, String username) {
        super();
        this.id = id;
        this.username = username;
    }
 
    public UserInfo(long id, String username, String password) {
        super();
        this.id = id;
        this.username = username;
        this.password = password;
        System.out.println("public UserInfo(long id, String username, String password)");
        System.out.println(id + " " + username + " " + password);
 
    }
 
    public long getId() {
        return id;
    }
 
    public void setId(long id) {
        this.id = id;
    }
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public String getPassword() {
        return password;
    }
 
    public void setPassword(String password) {
        this.password = password;
    }
 
    public void test() {
        System.out.println("public void test1()");
    }
 
    public void test(String address) {
        System.out.println("public void test2(String address) address=" + address);
    }
 
    public String test(int age) {
        System.out.println("public String test3(int age) age=" + age);
        return "我是返回值";
    }
}

    public static void main(String[] args) throws InstantiationException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
        Class<UserInfo> userInfoClass = UserInfo.class;
        //1、使用Class对象调用无参构造方法
        //UserInfo userInfo = userInfoClass.newInstance(); 已废弃，不推荐使用
        UserInfo userInfo = userInfoClass.getDeclaredConstructor().newInstance();
        userInfo.setId(666L);
        userInfo.setUsername("测试");
        System.out.println(userInfo.getUsername());
        //2、使用Class对象调用有参构造方法
        UserInfo userInfo1 = userInfoClass.getDeclaredConstructor(long.class, String.class, String.class).newInstance(1L, "张三", "123456");
 
    }