@PathVariable注解

转自：http://www.cnblogs.com/FFFFF/p/4624140.html

使用@PathVariable可以快速的访问，URL中的部分内容。

①. 在@RequestMapping的value中使用URI template（{变量名}），然后在@RequestMapping注解方法的需要绑定的参数前，使用@PathVariable指定变量名（如果变量名和参数名一致也可以不指定），从而将URL中的值绑定到参数上。

代码：

   1: @RequestMapping("/testPathVariable")
   2: @Controller
   3: public class TestPathVariable {
   4:  
   5:     /*
   6:     * URI模板指定了一个变量名为id的变量，当控制器处理请求时会将 id 替换为正确的值
   7:     *
   8:     * 若请求为 testPathVariable/user/29，则uid=29，输出29
   9:     *
  10:     * */
  11:     @RequestMapping("/user/{id}")
  12:     public String testPathVariable(@PathVariable("id") Integer uid) {
  13:         System.out.println(uid);
  14:         return "success";
  15:     }
  16:  
  17: }

URL:

   1: testPathVariable user 29

②. 一个方法可以有多个@PathVriable注解

URI template 可以这样，全部在方法上

代码：

   1: @RequestMapping("/testPathVariable")
   2: @Controller
   3: public class TestPathVariable {
   4:  
   5:     @RequestMapping("/user/{uid}/book/{bid}")
   6:     public String testMultiplePathVariable(@PathVariable("uid") Integer uid,@PathVariable("bid") Integer bid) {
   7:         System.out.println(uid);
   8:         System.out.println(bid);
   9:         return "success";
  10:     }
  11:  
  12: }

URL:

   1: testPathVariable user 29 book 101

URI template还可以这样， 加在类和方法上

代码：

   1: @RequestMapping("/testPathVariable/user/{uid}")
   2: @Controller
   3: public class TestPathVariable {
   4:  
   5:     @RequestMapping("/book/{bid}")
   6:     public String testMultiplePathVariable(@PathVariable("uid") Integer uid, @PathVariable("bid") Integer bid) {
   7:  
   8:         System.out.println(uid);
   9:         System.out.println(bid);
  10:         return "success";
  11:     }
  12:  
  13: }

URL:

  1: testPathVariable user 29 book 101

③. @PathVariable 还可以使用在 map 参数上，但是必须配置

代码：

   1: @RequestMapping("/testPathVariable/user/{uid}")
   2: @Controller
   3: public class TestPathVariable {
   4:  
   5:     @RequestMapping("/book/{bid}")
   6:     public String testMultiplePathVariable_Map(@PathVariable Map map) {
   7:         System.out.println(map.get("uid"));
   8:         System.out.println(map.get("bid"));
   9:         return "success";
  10:     }
  11:     
  12: }

URL：

   1: testPathVariable user 29 book 101

applicationContext.xml

   1: 

④. URI template 还支持正则表达式 。具体请看API

⑤. 使用@PathVariable可以让我们进行REST风格的编程，简单理解REST：对网络中某一资源的操作使用一个URI进行表示，然后使用状态来（GET、POST、PUT、DELETE）表示某种操作

原来对user进行CURD 使用了@PathVariable之后的CRUD
/user/get?id=10

/user/post?…

/user/update?id=10…

/user/delete?id=10

/user/id=10 RequestMethod.GET

/user/… RequestMethod.POST

/user/id=10… RequestMethod.PUT

/user/id=10 RequestMethod.DELETE

为了使普通表单支持PUT、DELETE请求，可以在POST请求下添加一个隐藏域（），然后在web.xml中配置HiddenHttpMethodFilter

对某用户的订单进行CRUD，代码：

   1: @RequestMapping("/testPathVariable/user/{uid}")
   2: @Controller
   3: public class TestPathVariable {
   4:  
   5:     /*
   6:     *获取某用户的所有订单
   7:     * */
   8:     @RequestMapping(value = "/order", method = RequestMethod.GET)
   9:     public String testGET(@PathVariable Integer uid) {
  10:         System.out.println("GET: " + " user-" + uid);
  11:         return "success";
  12:     }
  13:  
  14:     /*
  15:     * 获取某用户的某个订单详情
  16:     * */
  17:     @RequestMapping(value = "/order/{oid}", method = RequestMethod.GET)
  18:     public String testGET_OID(@PathVariable Integer uid, @PathVariable Integer oid) {
  19:         System.out.println("GET_OID: " + " user-" + uid + " order-" + oid);
  20:         return "success";
  21:     }
  22:  
  23:     /*
  24:     * 修改某用户的某个订单的总价
  25:     * params = {"total"}
  26:     *   若加params，则请求中必须有该变量,没有会报错。
  27:     *   如果不加params，则请求中不强制要求包含该变量
  28:     *   不包含时，则parameter中的对应变量值为为Null，
  29:     *       如请求/testPathVariable/user/29/order/101    
  30:     *       则total=null
  31:     *   包含，则parameter中的对应变量值为请求中的值
  32:     *       如请求/testPathVariable/user/29/order/101?total=1000   
  33:     *       则total=1000
  34:     * */
  35:     @RequestMapping(value = "/order/{oid}", method = RequestMethod.PUT, params = {"total"})
  36:     public String testPUT(@PathVariable Integer uid, @PathVariable Integer oid, Integer total) {
  37:         System.out.println("PUT: " + " user-" + uid + " order-" + oid);
  38:         System.out.println(total);
  39:         return "success";
  40:     }
  41:  
  42:     /*
  43:     * 新增某用户的订单,变量略
  44:     * */
  45:     @RequestMapping(value = "/order", method = RequestMethod.POST)
  46:     public String testPOST_(@PathVariable Integer uid) {
  47:         System.out.println("POST: " + " user-" + uid + " order：订单信息");
  48:         return "success";
  49:     }
  50:  
  51:     /*
  52:     * 删除某用户的某个订单
  53:     * */
  54:     @RequestMapping(value = "/order/{oid}", method = RequestMethod.DELETE)
  55:     public String testDELETE(@PathVariable Integer uid, @PathVariable Integer oid) {
  56:         System.out.println("GET: " + " user-" + uid + " order-" + oid);
  57:         return "success";
  58:     }
  59: }

index.jsp:

   1:  
   2: 

   3:     

   4:     
   5: 
   6:  
   7: 


   8: 

   9:     输入订单信息....

  10:     
  11: 
  12:  
  13: 


  14:  
  15: 

  16:     

  17:     

  18:     
  19: 
  20:  
  21: 


  22:  
  23:  
  24: 获取ID为29用户的所有订单
  25:  
  26: 


  27:  
  28: 获取ID为29的用户，ID为101的订单的详情
  29:  
  30: 


  31:  

在web.xml中配置HiddenHttpMethodFilter：

   1: 
   2:     hiddenHttpMethodFilter
   3:     org.springframework.web.filter.HiddenHttpMethodFilter
   4: 
   5: 
   6:     hiddenHttpMethodFilter
   7:     /*
   8: