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【SpringBoot WEB 系列】RestTemplate 之自定义请求头
source link: https://segmentfault.com/a/1190000023051624
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上一篇介绍了 RestTemplate 的基本使用姿势，在文末提出了一些扩展的高级使用姿势，本篇将主要集中在如何携带自定义的请求头，如设置 User-Agent，携带 Cookie
- Get 携带请求头
- Post 携带请求头
- 拦截器方式设置统一请求头
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I. 项目搭建
1. 配置
借助 SpringBoot 搭建一个 SpringWEB 项目，提供一些用于测试的 REST 服务
2.2.1.RELEASE spring-boot-stater-web
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
为了后续输出的日志更直观，这里设置了一下日志输出格式，在配置文件 application.yml 中，添加
logging:
pattern:
console: (%msg%n%n){blue}
2. Rest 服务
添加三个接口，分别提供 GET 请求，POST 表单，POST json 对象，然后返回请求头、请求参数、cookie，具体实现逻辑相对简单，也不属于本篇重点，因此不赘述说明
@RestController
public class DemoRest {
private String getHeaders(HttpServletRequest request) {
Enumeration<String> headerNames = request.getHeaderNames();
String name;
JSONObject headers = new JSONObject();
while (headerNames.hasMoreElements()) {
name = headerNames.nextElement();
headers.put(name, request.getHeader(name));
}
return headers.toJSONString();
}
private String getParams(HttpServletRequest request) {
return JSONObject.toJSONString(request.getParameterMap());
}
private String getCookies(HttpServletRequest request) {
Cookie[] cookies = request.getCookies();
if (cookies == null || cookies.length == 0) {
return "";
}
JSONObject ck = new JSONObject();
for (Cookie cookie : cookies) {
ck.put(cookie.getName(), cookie.getValue());
}
return ck.toJSONString();
}
private String buildResult(HttpServletRequest request) {
return buildResult(request, null);
}
private String buildResult(HttpServletRequest request, Object obj) {
String params = getParams(request);
String headers = getHeaders(request);
String cookies = getCookies(request);
if (obj != null) {
params += " | " + obj;
}
return "params: " + params + "\nheaders: " + headers + "\ncookies: " + cookies;
}
@GetMapping(path = "get")
public String get(HttpServletRequest request) {
return buildResult(request);
}
@PostMapping(path = "post")
public String post(HttpServletRequest request) {
return buildResult(request);
}
@Data
@NoArgsConstructor
public static class ReqBody implements Serializable {
private static final long serialVersionUID = -4536744669004135021L;
private String name;
private Integer age;
}
@PostMapping(path = "body")
public String postBody(@RequestBody ReqBody body) {
HttpServletRequest request =
((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
return buildResult(request, body);
}
}
II. 使用姿势
最常见的携带请求头的需求，无非是 referer 校验，user-agent 的防爬以及携带 cookie，使用 RestTemplate 可以借助 HttpHeaders 来处理请求头
1. Get 携带请求头
前一篇博文介绍了 GET 请求的三种方式，但是 getForObject / getForEntity 都不满足我们的场景，这里需要引入 exchange 方法
public void header() {
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.set("user-agent",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36");
headers.set("cookie", "my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;");
// 注意几个请求参数
HttpEntity<String> res = restTemplate
.exchange("http://127.0.0.1:8080/get?name=一灰灰&age=20", HttpMethod.GET, new HttpEntity<>(null, headers),
String.class);
log.info("get with selfDefine header: {}", res);
}
exchange 的使用姿势和我们前面介绍的 postForEntity 差不多，只是多了一个指定 HttpMethod 的参数而已
重点在于将请求头塞入 HttpEntity
输出结果
(get with selfDefine header: <200,params: {"name":["一灰灰"],"age":["20"]}
headers: {"cookie":"my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;","host":"127.0.0.1:8080","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"welcome_yhh"},[Content-Type:"text/plain;charset=UTF-8", Content-Length:"447", Date:"Mon, 29 Jun 2020 07:48:49 GMT"]>
2. Post 携带请求头
post 携带请求头，也可以利用上面的方式实现；当然我们一般直接借助 postForObject/postForEntity 就可以满足需求了
// httpHeaders 和上面的一致，这里省略相关代码
// post 带请求头
MultiValueMap<String, Object> params = new LinkedMultiValueMap<>();
params.add("name", "一灰灰Blog");
params.add("age", 20);
String response = restTemplate
.postForObject("http://127.0.0.1:8080/post", new HttpEntity<>(params, headers), String.class);
log.info("post with selfDefine header: {}", response);
输出结果
(post with selfDefine header: params: {"name":["一灰灰Blog"],"age":["20"]}
headers: {"content-length":"338","cookie":"my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;","host":"127.0.0.1:8080","content-type":"multipart/form-data;charset=UTF-8;boundary=2VJHo9r6lYgR_WoSBy1FQC40jvBvGtLk7QUaymGg","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"welcome_yhh"}
3. 拦截器方式
如果我们可以确定每次发起请求时，都要设置一个自定义的 User-Agent ，每次都使用上面的两种姿势就有点繁琐了，因此我们是可以通过拦截器的方式来添加通用的请求头，这样使用这个 RestTemplate 时，都会携带上请求头
// 借助拦截器的方式来实现塞统一的请求头
ClientHttpRequestInterceptor interceptor = (httpRequest, bytes, execution) -> {
httpRequest.getHeaders().set("user-agent",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36");
httpRequest.getHeaders().set("cookie", "my_user_id=haha123; UN=1231923;gr_user_id=interceptor;");
return execution.execute(httpRequest, bytes);
};
restTemplate.getInterceptors().add(interceptor);
response = restTemplate.getForObject("http://127.0.0.1:8080/get?name=一灰灰&age=20", String.class);
log.info("get with selfDefine header by Interceptor: {}", response);
上面这个使用姿势比较适用于通用的场景，测试输出
(get with selfDefine header by Interceptor: params: {"name":["一灰灰"],"age":["20"]}
headers: {"cookie":"my_user_id=haha123; UN=1231923;gr_user_id=interceptor;","host":"127.0.0.1:8080","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"interceptor"}
4. 请求头错误使用姿势
在我们使用自定义请求头时，有一个需要特殊重视的地方，HttpHeaders 使用不当，可能导致请求头爆炸
/**
* 错误的请求头使用姿势
*/
public void errorHeader() {
RestTemplate restTemplate = new RestTemplate();
int i = 0;
// 为了复用headers，避免每次都创建这个对象，但是在循环中又是通过 add 方式添加请求头，那么请求头会越来越膨胀，最终导致请求超限
// 这种case，要么将add改为set；要么不要在循环中这么干
HttpHeaders headers = new HttpHeaders();
while (++i < 5) {
headers.add("user-agent",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36");
headers.add("cookie", "my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;");
HttpEntity<String> res = restTemplate.exchange("http://127.0.0.1:8080/get?name=一灰灰&age=20", HttpMethod.GET,
new HttpEntity<>(null, headers), String.class);
log.info("get with selfDefine header: {}", res);
}
}
上面演示的关键点为
- 希望复用 HttpHeaders
-
headers.add方式添加请求头；而不是前面的set方式
输出如下，请注意每一次请求过后，请求头膨胀了一次
(get with selfDefine header: <200,params: {"name":["一灰灰"],"age":["20"]}
headers: {"cookie":"my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;","host":"127.0.0.1:8080","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"welcome_yhh"},[Content-Type:"text/plain;charset=UTF-8", Content-Length:"447", Date:"Mon, 29 Jun 2020 07:48:49 GMT"]>
(get with selfDefine header: <200,params: {"name":["一灰灰"],"age":["20"]}
headers: {"cookie":"my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;; my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;","host":"127.0.0.1:8080","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"welcome_yhh"},[Content-Type:"text/plain;charset=UTF-8", Content-Length:"503", Date:"Mon, 29 Jun 2020 07:48:49 GMT"]>
(get with selfDefine header: <200,params: {"name":["一灰灰"],"age":["20"]}
headers: {"cookie":"my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;; my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;; my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;","host":"127.0.0.1:8080","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"welcome_yhh"},[Content-Type:"text/plain;charset=UTF-8", Content-Length:"559", Date:"Mon, 29 Jun 2020 07:48:49 GMT"]>
(get with selfDefine header: <200,params: {"name":["一灰灰"],"age":["20"]}
headers: {"cookie":"my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;; my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;; my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;; my_user_id=haha123; UN=1231923;gr_user_id=welcome_yhh;","host":"127.0.0.1:8080","connection":"keep-alive","accept":"text/plain, application/json, application/*+json, */*","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
cookies: {"my_user_id":"haha123","UN":"1231923","gr_user_id":"welcome_yhh"},[Content-Type:"text/plain;charset=UTF-8", Content-Length:"615", Date:"Mon, 29 Jun 2020 07:48:49 GMT"]>
II. 其他
0. 项目&系列博文
系列博文
源码
- 工程： https://github.com/liuyueyi/spring-boot-demo
- 项目: https://github.com/liuyueyi/spring-boot-demo/tree/master/spring-boot/221-web-resttemplate
1. 一灰灰 Blog
尽信书则不如，以上内容，纯属一家之言，因个人能力有限，难免有疏漏和错误之处，如发现 bug 或者有更好的建议，欢迎批评指正，不吝感激
下面一灰灰的个人博客，记录所有学习和工作中的博文，欢迎大家前去逛逛
- 一灰灰 Blog 个人博客 https://blog.hhui.top
- 一灰灰 Blog-Spring 专题博客 http://spring.hhui.top
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