18.3.2从Class上获取信息(构造器)

Posted 2020-10-02 奋斗的少年WH

获取构造器信息

package d18_3_1;

import java.lang.reflect.Constructor;
import java.util.Arrays;
/**
 * 获取构造器的四个方法
 * 
 * 运行结果如下
 * [private d18_3_1.Test2(), public d18_3_1.Test2(java.lang.String,int,java.lang.String), public d18_3_1.Test2(java.lang.String,int), protected d18_3_1.Test2(java.lang.String)]
 * protected d18_3_1.Test2(java.lang.String)
 * [public d18_3_1.Test2(java.lang.String,int,java.lang.String), public d18_3_1.Test2(java.lang.String,int)]
 * public d18_3_1.Test2(java.lang.String,int)
 */
public class ClassInfo1 {

	public static void main(String[] args) throws NoSuchMethodException, SecurityException {
		// 获取构造器的四个方法
		Class c = Test2.class;
		// 1 获取所有的构造器，不论是否私有
		Constructor[] dcs1 = c.getDeclaredConstructors();
		System.out.println(Arrays.toString(dcs1));
		// 2获取在所有构造器中，指定的构造器
		Constructor dc1=c.getDeclaredConstructor(String.class);
		System.out.println(dc1); 
		// 3 获取所有public构造器
		Constructor[] dcs2 = c.getConstructors();
		System.out.println(Arrays.toString(dcs2));
		// 4在所有public构造器中，获取指定的构造器
		Constructor dc2=c.getConstructor(String.class,int.class);
		System.out.println(dc2); 
	}

}

class Test2 {
	private String name;
	private int age;
	String sex;

	private Test2() {

	}

	protected Test2(String name) {
		super();
		this.name = name;
	}

	public Test2(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}

	public Test2(String name, int age, String sex) {
		super();
		this.name = name;
		this.age = age;
		this.sex = sex;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Test [name=" + name + ", age=" + age + "]";
	}

}