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怎么将某个http请求映射到某个方法上？SpringBoot入门：URL 映射

php是最好的语言原创: 2018-07-27 10:24:025815浏览

0x000 概述：将某个http请求映射到某个方法上。0x001 @RequestMapping：这个注解可以加在某个Controller或者某个方法上，如果加在Controller上

0x000 概述

将某个http请求映射到某个方法上

0x001 `@RequestMapping`

这个注解可以加在某个Controller或者某个方法上，如果加在Controller上，则这个Controller中的所有路由映射都将会加上这个前缀（下面会有栗子），如果加在方法上，则没有前缀（下面也有栗子）。

@RequestMapping有以下属性

value: 请求的URL的路径
path: 和value一样
method: 请求的方法
consumes: 允许的媒体类型，也就是Content-Type
produces: 相应的媒体类型，也就是Accept
params: 请求参数
headers: 请求头部

0x002 路由匹配

首先编写Controller，Controller头部的@RestController将这个控制器标注为Rest控制器：

package com.lyxxxx.rest.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

}

添加方法，并添加URL匹配：
```
    @RequestMapping()
    public Object hello() {
        return "hello";
    }
```
说明：上面添加了一个方法，名为hello，没有给定任何的属性，则默认匹配所有URL，方法为GET，所以我们可以直接使用GET方式来访问该路由
```
$ curl 127.0.0.1:8080
hello
$ curl 127.0.0.1:8080/user
hello
$ curl 127.0.0.1:8080/user/1
hello
```

精确匹配

@RequestMapping(value = "/hello2")
public Object hello2() {
    return "hello2";
}

说明：上面将value设置为hello2，所以访问hello2将会执行hello2方法
$ curl 127.0.0.1:8080/hello2
hello2

字符模糊匹配

@RequestMapping(value = "/hello3/*")
public Object hello3() {
    return "hello3";
}

说明：上面将value设置为/hello3/*,*为匹配所有字符，也就是访问hello3下的所有URL都将匹配该防范
$ curl 127.0.0.1:8080/hello3/user
hello3
 curl 127.0.0.1:8080/hello3/1
hello3

单字符模糊匹配

$ curl 127.0.0.1:8080/hello4/1
hello4

说明：上面将value设置为/hello4/?,?为匹配单个字符，匹配hello4/1，但是不会匹配hello4/11
$ curl 127.0.0.1:8080/hello4/1
hello4
$ curl 127.0.0.1:8080/hello4/12
{"timestamp":"2018-07-25T05:29:39.105+0000","status":404,"error":"Not Found","message":"No message available","path":"/hello4/12"}

全路径模糊匹配

@RequestMapping(value = "/hello5/**")
public Object hello5() {
    return "hello5";
}

说明：上面将value设置为/hello5/**,**为匹配所有路径，所以hello5下面的所有路由都将匹配这个方法
$ curl 127.0.0.1:8080/hello5
hello5
$ curl 127.0.0.1:8080/hello5/user/1
hello5

多个路径匹配

@RequestMapping(value = {"/hello6", "/hello6/1"})
public Object hello6() {
    return "hello6";
}

$ curl 127.0.0.1:8080/hello6
hello6
$ curl 127.0.0.1:8080/hello6/1
hello6F

读取配置

// resources/application.properties

app.name=hello7

// com.lyxxxx.rest.controller.HelloController

@RequestMapping(value = "${app.name}")
public Object hello7() {
    return "hello7";
}

$ curl 127.0.0.1:8080/hello7
hello7

0x003 方法匹配

匹配请求中的method，写在RequestMethod中的枚举值：

GET
HEAD
POST
PUT
PATCH
DELETE
OPTIONS
TRACE

package com.lyxxxx.rest.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MethodController {
    @RequestMapping(path = "method/get", method = RequestMethod.GET)
    public Object get() {
        return "get";
    }

    @RequestMapping(path = "method/head", method = RequestMethod.HEAD)
    public Object head() {
        return "head";
    }

    @RequestMapping(path = "method/post", method = RequestMethod.POST)
    public Object post() {
        return "post";
    }

    @RequestMapping(path = "method/put", method = RequestMethod.PUT)
    public Object put() {
        return "put";
    }

    @RequestMapping(path = "method/patch", method = RequestMethod.PATCH)
    public Object patch() {
        return "patch";
    }

    @RequestMapping(path = "method/delete", method = RequestMethod.DELETE)
    public Object delete() {
        return "delete";
    }

    @RequestMapping(path = "method/options", method = RequestMethod.OPTIONS)
    public Object options() {
        return "options";
    }

    @RequestMapping(path = "method/trace", method = RequestMethod.TRACE)
    public Object trace() {
        return "trace";
    }


}

$ curl -X GET  127.0.0.1:8080/method/get
get
$ curl -X POST 127.0.0.1:8080/method/post
post
$ curl -X DELETE 127.0.0.1:8080/method/delete
delete
$ curl -X PUT 127.0.0.1:8080/method/put
put
...

0x003 params 匹配

除了可以匹配URL和method之外，还可以匹配params

package com.lyxxxx.rest.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ParamsController {
    @RequestMapping(path = "/params", params = "userId=1")
    public Object params() {
        return "params";
    }
}

$ curl 127.0.0.1:8080/params?userId=1
params

0x004 说明

以上参考数据：《Spring Boot2精髓从构建小系统到架构分部署大系统》

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