反射之类的加载和创建对象

public class ReflectTest01 {
    public static void main(String[] args) throws ClassNotFoundException {
        //第一种方式
        Class c1 = Class.forName("Employee");//c1引用保存地址指向堆中的对象，该对象代表的是Employee整个类
        
        //第二种方式
        //Java中每个类都有class属性
        Class c2 = Employee.class;
        
        //第三种方式
        //java语言中任何一个java对象都有getClass 方法
        Employee e = new 获得类的加载.Employee();
睿共享        Class c3 = e.getClass();
        
        //因为Employee这个类在jvm中只有一个，，所以c1,c2,c3 的内存地址是相同的，指向堆中唯一的一个对象
        System.out.println(c1==c2);//双等号两边如果是跟引用数据类型     ---->比较的是内存地址     
        System.out.println(c2==c3);
        
        //c4，c5，c6 都代表  date这个类
        Class c4 = Date.class; //c4代表 Date这个类
        Class c5 = Class.forName("java.lang.Date");  // 必须写类全名，类全名带有包名
        Date d = new Date(0);
        Class c6 = d.getClass();
        
    }

}
class Employee {
    //Field 字段
    private String name;
    
    //无参
    public Employee() {}
    //Constructor 构造函数
    public Employee(String name) {
        this.name = name;
    }
    
    //方法
    public睿共享 void work() {
        System.out.println(name + "在工作");
    }

}

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新建一个实体类

//实体类
public class User {
    private Integer id;//id
    private String userCode;//用户编码
    private String userName;//用户名称
    private String userPassword;//用户密码
    private int gerder;//性别
    private Date birthday;//出生日期
    private St睿共享ring phone;//电话
    private String address;//地址
    private Integer age;//年龄
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUserCode() {
        return userCode;
    }
    public void setUserCode(String userCode) {
        this.userCode = userCode;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getUserPassword() {
        return userPassword;
    }
    public void setUserPassword(String userPassword) {
        this.userPassword = userPassword;
    }
    public int getGerder() {
        return gerder;
    }
    public void setGerder(int gerder) {
        this.gerder = gerder;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
  睿共享  public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userCode='" + userCode + ''' +
                ", userName='" + userName + ''' +
                ", userPassword='" + userPassword + ''' +
                ", gerder=" + gerder +
                ", birthday=" + birthday +
                ", phone='" + phone + ''' +
                ", address='" + address + ''' +
                ", age=" + age +
                '}';
    }

    public User(Integer id, String userCode, String userName) {
        this.id = id;
        this.userCode = userCode;
        this.userName = userName;

    }
    public User() {
    }
}

User user = new User();

//1反射创建对象第一种方法
Object o = c.newInstance();
//複製上去
User user1 = (User)o;
user1.setId(1);
user1.setUserCode("admin");
user1.setUserName("李四");
System.out.println(user1);


Constructor[] constructors = c.getConstructors();
for (Constructor constructor : constructors){
    System.out.println("constructor"+constructor);
}
//2反射创建对象第二种方法   //通过构造方法   通过class对象获取构造器 然后newInstance
Constructor constructor = c.getConstructor(Integer.class,String.class,String.class);
Object o1 = constructor.newInstance(1, "刘思", "admin");
if(o1 instanceof User){
    User user2 = (User) o1;
    System.out.println(user2);
}

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练习反射

public class ArticleTypeBean {
   private int id = -1;
   private String typeName = "";
   private String typeInfo = "";

   public int getId() {
      return id;
   }

   public void setId(int id) {
      this.id = id;
   }

   public String getTypeInfo() {
      return typeInfo;
   }

   public void setTypeInfo(String typeInfo) {
      this.typeInfo = typeInfo;
   }

   public String getTypeName() {
      return typeName;
   }

   public void setTypeName(String typeName) {
      this.typeName = typeName;
   }

   @Test
   public void test() throws ClassNotFoundException, NoSuchFieldException, NoSuchMethodException {
      Class c = Class.forName("com.rzk.valuebean.ArticleTypeBean");
      //获得类的名字
      System.out.println(c.getName());//获得包名和类名
      System.out.println(c.getSimpleName());//获得类名

      //获得类的属性
      Field[] fields = c.getFields();//获得类的公开属性
      fields = c.getDeclaredFields();//获得该类的全部属性
      for (Field fs : fields){
         System.out.println(fs);
      }
      //获得指定属性的值
      System.out.println("----------华丽的分割线----------");
      Field name = c.getDeclaredField("typeName");
      System.out.println(name);

      System.out.println("-------有是一条华丽的分割线-------");

      //获得类的方法
      Method[] methods = c.getMethods();//获得本类及其父类的全部public方法
      for (Method m : methods){
         System.out.println(m);
      }
      methods = c.getDeclaredMethods();//获得本类的所有方法
      for (Method method : methods){
         System.out.println("getDeclareMethods "+method);
      }

      //获得指定的方法  要赋值
      Method typeName = c.getMethod("getTypeName");
      Method setTypeName = c.getMethod("setTypeName",String.class);
      System.out.println(typeName);睿共享
      System.out.println(setTypeName);
      System.out.println("-------有是一条华丽的分割线-------");
      //获得指定的构造器
      Constructor[] constructors = c.getConstructors();
      for (Constructor constructor:constructors){
         System.out.println(c);
      }

      constructors = c.getDeclaredConstructors();
      for (Constructor constructor : constructors){
         System.out.println(constructor);
      }
      System.out.println("-------有是一条华丽的分割线-------");
      Constructor declaredConstructor = c.getDeclaredConstructor();
      System.out.println("指定的构造器 = "+declaredConstructor);

   }