[代码记录生活]利用注解实现权限验证

定义注解:

package app;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Retention(RetentionPolicy.RUNTIME)
public @interface PrivilegeAnnotation {
  String model(); //模块
  String pivilegeValue();//权限名
}

使用注解:

public class StudentAction {	
	
         //student 模板中的add方法
	@PrivilegeAnnotation(model="student",pivilegeValue="add")
	public void add() {
         System.out.println("add student......");
	}

	@PrivilegeAnnotation(model="student",pivilegeValue="update")
	public void update() {
         System.out.println("update student.......");
	}

	@PrivilegeAnnotation(model="student",pivilegeValue="delete")
	public void delete() {
         System.out.println("delete ...............");
	}
         
         //select 为所有用户都能查看
	public void select() {
         System.out.println("select...............");
	}

}

创建一个Privilege类，存放用户访问信息

  public class Privilege {
	private String uname;  //用户名
	private String model;  ////模块
	private String privilegeValue;  //权限名

           ..... get set 方法
  }

  public class PrivilegeService {
	//获得用户的所有权限
	public static ArrayList<Privilege> getPrivilege(String 

uname){
		ArrayList<Privilege> list=new ArrayList<Privilege>();
		if("admin".equals(uname)){
			list.add(new Privilege("admin", 

"student", "add"));
			list.add(new Privilege("admin", 

"student", "update"));
			list.add(new Privilege("admin", 

"student", "delete"));			
		}else {
			list.add(new Privilege("andy", 

"student", "add"));
		}
		
		return list;
	}

}

/**
 * 进行权限管理
 * @author zhou
 *
 */
public class PrivilegeManager {

	private StudentAction action;
//-------------------------------------------------------------
	
	//b/s模式中不需要传action  接收一个StudentAction类
	public PrivilegeManager(StudentAction action) {
		this.action=action;
	}
//-------------------------------------------------------------
         //权限验证,b/s不需要传name   uname:用户名    methodName:方法名
	public void validate(String uname,String methodName){
		//1.
		Method method=this.getMethod(methodName);
//-------------------------------------------------------------

	//2.
	PrivilegeAnnotation annotation=this.getAnnotation(method);
//-------------------------------------------------------------

		
		if(annotation!=null){
		//3.根据注解和传入的用户名，得到Privilege对象
		//根据注解和传入的用户名，得到Privilege对象
		Privilege privilege=new Privilege();
		privilege.setUname(uname);
		privilege.setModel(annotation.model()); //获得注解中的模块名称
	privilege.setPrivilegeValue(annotation.pivilegeValue());//获得注解中的访问操作	

//-------------------------------------------------------------
	
		//得到该用户的所有权限
	ArrayList<Privilege> list=PrivilegeService.getPrivilege(uname);
		
		//判断该用户是否有权限
                     //contains list中是否存在指定对象
		if(list.contains(privilege)){ //存在
			this.doMethod(method); //调用方法
		}else{  //不存在
			System.out.println("没有权限");
		}
		
		}else{
			this.doMethod(method); //调用方法
		}
	}
//-------------------------------------------------------------

	//得到方法名对应的Method对象
	private Method getMethod(String methodName){
		Method method=null;
		try {
                           //从StudentAction类中得到对应的方法
			method=this.action.getClass

().getDeclaredMethod(methodName);
		} catch (SecurityException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return method;
	}

//-------------------------------------------------------------

	//再将方法传入进来 得到注解对象
	private PrivilegeAnnotation getAnnotation(Method 

method){
		PrivilegeAnnotation annotation=null;
		if (method.isAnnotationPresent

(PrivilegeAnnotation.class)){
			annotation=method.getAnnotation

(PrivilegeAnnotation.class);
		}
		
		return annotation;
	}
} 

  public class Demo {
	public static void main(String[] args) {
		StudentAction action=new StudentAction();

        PrivilegeManager manager=new PrivilegeManager(action);
        manager.validate("admin","select");
        manager.validate("admin","update");
        manager.validate("admin","delete");
        manager.validate("admin","add");
        System.out.println("------andy--------------");
        manager.validate("andy","select");
        manager.validate("andy","update");
        manager.validate("andy","delete");
        manager.validate("andy","add");
        System.out.println("------jack--------------");
        manager.validate("jack","select");
        manager.validate("jack","update");
        manager.validate("jack","delete");
        manager.validate("jack","add");
        }
  }

输出结果:

select...............
update student.......
delete ...............
add student......
------andy--------------
select...............
没有权限
没有权限
add student......
------jack--------------
select...............
没有权限
没有权限
没有权限

用b/s模式做的话，则是跳转各页面，自行参考。