Java反射-＞什么是反射？-＞获取方式

Class<Student> student02 = Student.class;

Class<Student> student01 = (Class<Student>) Class.forName("com.zking.jee08.Student");

Student student = new Student();
Class<Student> student03 = (Class<Student>) student.getClass();

package com.zking.relfect.entity;
public class Student {
  private String sid;
  private String sname;
  public Integer age;
  String sex;
  public Student() {
  super();
  System.out.println("调用无参构造方法创建了一个学生对象");
  }
  public Student(String sid) {
  super();
  this.sid = sid;
  System.out.println("调用第一个参数的构造方法创建了一个学生对象");
  }
  public Student(String sid, String sname) {
  super();
  this.sid = sid;
  this.sname = sname;
  System.out.println("调用第二个参数的构造方法创建了一个学生对象");
  }
  @SuppressWarnings("unused")
  private Student(Integer age) {
  System.out.println("调用Student类私有的构造方法创建一个学生对象");
  this.age = age;
  }
  public String getSid() {
  return sid;
  }
  public void setSid(String sid) {
  this.sid = sid;
  }
  public String getSname() {
  return sname;
  }
  public void setSname(String sname) {
  this.sname = sname;
  }
  public void hello() {
  System.out.println("你好！我是" + this.sname);
  }
  public void hello(String name) {
  System.out.println(name + "你好！我是" + this.sname);
  }
  @SuppressWarnings("unused")
  private Integer add(Integer a, Integer b) {
  return new Integer(a.intValue() + b.intValue());
  }
}

//直接new获取对象
Student student04 = new Student();
//通过反射的方式获取对象  
Class<Student> Student05 = Student.class;
Student stu= Student05.newInstance();//调用无参的构造方法，开始实例化
stu.setSid("01");
stu.setSname("张三");
System.out.println(stu.getSname());

Constructor<Student> stu= Student05.getConstructor(String.class);
  Student stu01 = stu.newInstance("02");//开始实例化
  System.out.println(stu01.getSid());

Constructor<Student> stu04= Student05.getDeclaredConstructor(Integer.class);
  stu04.setAccessible(true);//打开访问权限
  Student stu004 = stu04.newInstance(1);
  System.out.println(stu004.getAge());

//加载反射
  @SuppressWarnings("unchecked")
  Class<Student> student = (Class<Student>) Class.forName("com.zking.jee08.Student");
  Student stu= student.newInstance();
  stu.setSid("01");
  stu.setSname("张三");

//通过反射调用hello无参方法
  Method stu01 = student.getMethod("hello");
  //开始加载对象
  Student in01 = (Student) stu01.invoke(stu);//stu是实例化对象，要在哪个实例化对象里面加载
  System.out.println(in01);
//通过反射调用hello有参的方法
  Method stu02 = student.getMethod("hello", String.class);
  //开始加载对象
  Student in02= (Student) stu02.invoke(stu,"张三");
  System.out.println(in02);

//加载反射
  @SuppressWarnings("unchecked")
  Class<Student> student = (Class<Student>) Class.forName("com.zking.jee08.Student");
  Student stu = student.newInstance();
  stu.setSid("01");
  stu.setSname("张三");
  stu.setAge(10);

//定义获取sid属性值
  Field f1 = student.getDeclaredField("sid");
  f1.setAccessible(true);
  //从stu对象里面获取属性值
  String get1 = (String) f1.get(stu);//stu是实例化对象，要在哪个实例化对象里面调用属性
  System.out.println(get1);

Field[] f4 = student.getDeclaredFields();
  for (Field f : f4) {
    f.setAccessible(true);
    System.out.println(f.getName()  +":" + f.get(stu));//stu是实例化对象，要在哪个实例化对象里面调用属性
  }