反射获取构造器对象

java通过字节对象可以获取class类中的构造函数，以下三种分别为获取无参的构造函数、公有的构造函数和私有的构造函数。

people对象的代码如下：

public class People {private String name;private String sex;private int age;public People(){System.out.println("构造方法被调用了啊！");}public People(String name){this.name=name;System.out.println("构造方法被调用了啊！+String");}public People(int age){this.age=age;System.out.println("构造方法被调用了啊！+int");}private People(String name,String sex){this.name=name;this.sex=sex;System.out.println("构造方法被调用了啊！+name  +sex");}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}

获取构造函数的方法如下：

public class ConstructorGetDemo {/*** 获取无参数的构造函数*/@Testpublic void test1() throws Exception{//通过类获取class对象Class clazz1= Class.forName("com.wzd.tool.People");//获取只有一个无参的构造器Constructor<People> constructor=clazz1.getConstructor(null);//实例化构造器People people=constructor.newInstance();//打印people对象的名字System.out.println(people.getName());}/*** 获取有参的共有的构造函数*/@Testpublic void test2() throws Exception{//通过类获取class对象Class<People> clazz1=People.class;//获取只有一个String参数的构造器Constructor<People> constructor=clazz1.getConstructor(String.class);//传入String值实例化构造器People people=constructor.newInstance("张三");//打印people对象的名字System.out.println(people.getName());}/*** 获取私有的构造函数*/@Testpublic void test3() throws Exception{//通过类获取class对象Class<People> clazz1=People.class;//获取只有一个String参数的构造器Constructor<People> constructor=clazz1.getDeclaredConstructor(String.class,String.class);//设置可以访问私有的构造函数constructor.setAccessible(true);//传入String值实例化构造器People people=constructor.newInstance("张三","男");//打印people对象的名字System.out.println("姓名："+people.getName());System.out.println("性别:"+people.getSex());}}