spring3 的restful API RequestMapping介绍

原文链接：http://www.cnblogs.com/AloneSword/p/4099142.html

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 {
//
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class SubsystemDemoApplication {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SubsystemDemoApplication.class, args);
    }

}

 
可以从这里看到所有的示例https://github.com/eugenp/tutorials/tree/master/springmvc