java高级特性之反射(二)

java反射覆盖

功能：用于某个对象的新旧值进行更新覆盖操作。用途：常用于电商系统订单以及商品的新旧更新。

具体代码：下面以学生实体类进行讲解。

/**

• 学生类
  */
  public class Student {
  private Integer sid;
  private String sname;
  private Integer age;
  private String gender;

  public Student(int sid, String sname, int age, String gender) {
  this.sid = sid;
  this.sname = sname;
  this.age = age;
  this.gender = gender;
  }

  public Student(String sname, Integer age, String gender) {
  this.sname = sname;
  this.age = age;
  this.gender = gender;
  }

  public Student() {
  }

  public Integer getSid() {
  return sid;
  }

  public void setSid(Integer sid) {
  this.sid = sid;
  }

  public Integer getAge() {
  return age;
  }

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

  public String getSname() {
  return sname;
  }

  public void setSname(String sname) {
  this.sname = sname;
  }

  public String getGender() {
  return gender;
  }

  public void setGender(String gender) {
  this.gender = gender;
  }

  @Override
  public String toString() {
  return “Student{” +
  “sid=” + sid +
  “, sname=’” + sname + ‘’’ +
  “, age=” + age +
  “, gender=’” + gender + ‘’’ +
  ‘}’;
  }
  }

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Date;

/**

• 反射工具类
  */
  public class ReflectUtils {

  /**

  • 反射覆盖

  */
  public static void saveOrupdate(Object s1,Object s2) throws Exception{
  Class c1=s1.getClass();
  Class c2=s2.getClass();
  Field[] fields=c1.getDeclaredFields();
  for(Field field:fields) {
  field.setAccessible(true);
  String name = field.getName(); // 获取属性的名字
  name = name.substring(0, 1).toUpperCase() + name.substring(1); // 将属性的首字符大写，方便构造get，set方法
  String type = field.getGenericType().toString(); // 获取属性的类型
  if (type.equals(“class java.lang.String”)) { // 如果type是类类型，则前面包含"class "，后面跟类名
  Method m = c2.getMethod(“get” + name);
  String value = (String) m.invoke(s2); // 调用getter方法获取属性值
  field.set(s1,value);
  }
  if (type.equals(“class java.lang.Integer”)) {
  Method m = c2.getMethod(“get” + name);
  Integer value = (Integer) m.invoke(s2);
  field.set(s1,value);
  }

       if (type.equals("class java.lang.Boolean")) {
           Method m = c2.getMethod("get" + name);
           Boolean value = (Boolean) m.invoke(s2);
           field.set(s1,value);
       }
       if (type.equals("class java.util.Date")) {
           Method m = c2.getMethod("get" + name);
           Date value = (Date) m.invoke(s2);
           field.set(s1,value);
       }
   }
  

  }

  public static void main(String[] args) {
  Student s1=new Student(1,“张三”,24,“男”);
  Student s2=new Student(“赵薇”,38,“女”);
  try {
  saveOrupdate(s1,s2);
  } catch (Exception e) {
  e.printStackTrace();
  }
  System.out.println(s1.toString());

  }
  }