spring3 的restful API RequestMapping介绍

原文链接：http://www.javaarch.net/jiagoushi/694.htm

spring3 的restful API RequestMapping介绍  
  
在spring mvc中 @RequestMapping是把web请求映射到controller的方法上。  
  
1.RequestMapping Basic Example  
  将http请求映射到controller方法的最直接方式  
1.1 @RequestMapping  by Path  
   
    @RequestMapping(value = "/foos")  
    @ResponseBody  
    public String getFoosBySimplePath() {  
        return "Get some Foos";  
    }  
      
可以通过下面的方式测试： curl -i http://localhost:8080/springmvc/foos  
  
1.2 @RequestMapping – the HTTP Method，我们可以加上http方法的限制  
  
    @RequestMapping(value = "/foos", method = RequestMethod.POST)  
    @ResponseBody  
    public String postFoos() {  
        return "Post some Foos";  
    }  
      
可以通过curl i -X POST http://localhost:8080/springmvc/foos测试。  
  
2.RequestMapping 和http header  
  
2.1 @RequestMapping with the headers attribute  
  当request的header包含某个key value值时  
      
    @RequestMapping(value = "/foos", headers = "key=val")  
    @ResponseBody  
    public String getFoosWithHeader() {  
        return "Get some Foos with Header";  
    }  
      
  header多个字段满足条件时  
    
    @RequestMapping(value = "/foos", headers = { "key1=val1", "key2=val2" })  
    @ResponseBody  
    public String getFoosWithHeaders() {  
        return "Get some Foos with Header";  
    }  
      
通过curl -i -H "key:val" http://localhost:8080/springmvc/foos 测试。  
  
2.2 @RequestMapping 和Accept头  
  
    @RequestMapping(value = "/foos", method = RequestMethod.GET, headers = "Accept=application/json")  
    @ResponseBody  
    public String getFoosAsJsonFromBrowser() {  
        return "Get some Foos with Header Old";  
    }  
支持accept头为json的请求，通过curl -H "Accept:application/json,text/html" http://localhost:8080/springmvc/foos测试  
  
在spring3.1中@RequestMapping注解有produces和 consumes 两个属性来代替accept头  
  
    @RequestMapping(value = "/foos", method = RequestMethod.GET, produces = "application/json")  
    @ResponseBody  
    public String getFoosAsJsonFromREST() {  
        return "Get some Foos with Header New";  
    }  
同样可以通过curl -H "Accept:application/json" http://localhost:8080/springmvc/foos测试  
  
produces可以支持多个  
  
    @RequestMapping(value = "/foos", produces = { "application/json", "application/xml" })  
      
当前不能有两个方法同时映射到同一个请求，要不然会出现下面这个异常  
  
    Caused by: java.lang.IllegalStateException: Ambiguous mapping found.   
    Cannot map 'fooController' bean method  
    public java.lang.String org.baeldung.spring.web.controller.FooController.getFoosAsJsonFromREST()  
    to {[/foos],methods=[GET],params=[],headers=[],consumes=[],produces=[application/json],custom=[]}:   
    There is already 'fooController' bean method  
    public java.lang.String org.baeldung.spring.web.controller.FooController.getFoosAsJsonFromBrowser()   
    mapped.  
      
3.RequestMapping with Path Variables  
3.1我们可以把@PathVariable把url映射到controller方法  
    单个@PathVariable参数映射  
      
    @RequestMapping(value = "/foos/{id}")  
    @ResponseBody  
    public String getFoosBySimplePathWithPathVariable(@PathVariable("id") long id) {  
       return "Get a specific Foo with id=" + id;  
    }  
  
通过curl http://localhost:8080/springmvc/foos/1试试  
如果参数名跟url参数名一样，可以省略为  
  
    @RequestMapping(value = "/foos/{id}")  
    @ResponseBody  
    public String getFoosBySimplePathWithPathVariable(@PathVariable String id) {  
       return "Get a specific Foo with id=" + id;  
    }  
3.2 多个@PathVariable  
    
    @RequestMapping(value = "/foos/{fooid}/bar/{barid}")  
    @ResponseBody  
    public String getFoosBySimplePathWithPathVariables(@PathVariable long fooid, @PathVariable long barid) {  
        return "Get a specific Bar with id=" + barid + " from a Foo with id=" + fooid;  
    }  
      
通过curl http://localhost:8080/springmvc/foos/1/bar/2测试。  
  
3.3支持正则的@PathVariable   
    
    @RequestMapping(value = "/bars/{numericId:[\d]+}")  
    @ResponseBody  
    public String getBarsBySimplePathWithPathVariable(@PathVariable final long numericId) {  
        return "Get a specific Bar with id=" + numericId;  
    }  
  
这个url匹配：http://localhost:8080/springmvc/bars/1  
不过这个不匹配：http://localhost:8080/springmvc/bars/abc  
  
4.RequestMapping with Request Parameters  
  
我们可以使用 @RequestParam注解把请求参数提取出来  
比如url：http://localhost:8080/springmvc/bars?id=100  
  
    @RequestMapping(value = "/bars")  
    @ResponseBody  
    public String getBarBySimplePathWithRequestParam(@RequestParam("id") long id) {  
        return "Get a specific Bar with id=" + id;  
    }  
      
我们可以通过RequestMapping定义参数列表  
  
    @RequestMapping(value = "/bars", params = "id")  
    @ResponseBody  
    public String getBarBySimplePathWithExplicitRequestParam(@RequestParam("id") long id) {  
        return "Get a specific Bar with id=" + id;  
    }  
      
和  
  
    @RequestMapping(value = "/bars", params = { "id", "second" })  
    @ResponseBody  
    public String getBarBySimplePathWithExplicitRequestParams(@RequestParam("id") long id) {  
        return "Narrow Get a specific Bar with id=" + id;  
    }  
      
比如http://localhost:8080/springmvc/bars?id=100&second=something会匹配到最佳匹配的方法上，这里会映射到下面这个。  
  
5.RequestMapping Corner Cases  
  
5.1 @RequestMapping多个路径映射到同一个controller的同一个方法  
  
    @RequestMapping(value = { "/advanced/bars", "/advanced/foos" })  
    @ResponseBody  
    public String getFoosOrBarsByPath() {  
        return "Advanced - Get some Foos or Bars";  
    }  
      
下面这两个url会匹配到同一个方法  
  
    curl -i http://localhost:8080/springmvc/advanced/foos  
    curl -i http://localhost:8080/springmvc/advanced/bars  
      
5.2@RequestMapping 多个http方法 映射到同一个controller的同一个方法  
  
    @RequestMapping(value = "/foos/multiple", method = { RequestMethod.PUT, RequestMethod.POST })  
    @ResponseBody  
    public String putAndPostFoos() {  
        return "Advanced - PUT and POST within single method";  
    }  
下面这两个url都会匹配到上面这个方法  
  
    curl -i -X POST http://localhost:8080/springmvc/foos/multiple  
    curl -i -X PUT http://localhost:8080/springmvc/foos/multiple  
      
5.3@RequestMapping 匹配所有方法  
  
    @RequestMapping(value = "*")  
    @ResponseBody  
    public String getFallback() {  
        return "Fallback for GET Requests";  
    }  
  
匹配所有方法  
      
    @RequestMapping(value = "*", method = { RequestMethod.GET, RequestMethod.POST ... })  
    @ResponseBody  
    public String allFallback() {  
        return "Fallback for All Requests";  
    }  
      
6.Spring Configuration  
  
controller的annotation  
  
    @Controller  
    public class FooController { ... }  
      
spring3.1  
  
    @Configuration  
    @EnableWebMvc  
    @ComponentScan({ "org.baeldung.spring.web.controller" })  
    public class MvcConfig {  
        //  
    }  
      
可以从这里看到所有的示例https://github.com/eugenp/tutorials/tree/master/springmvc