本文共 8219 字，大约阅读时间需要 27 分钟。

1 url传递参数

这个和get没有啥区别，就简单介绍

1. 服务提供者

/**     * 测试一个参数     *     * @return     */    @PostMapping("/post")    public String test01(@RequestParam String name) {           return name;    }    /**     * 测试Map     *     * @return     */    @PostMapping("/post/map")    public String test02(@RequestParam Map
   
     map) {           return map.toString();    }
   

2. 客户端

/**  * 测试一个参数  *  * @return  */ @RequestLine("POST /feign/provider/post?name={name}") String invokeTest01(@Param(value = "name") String name); /**  * 测试map  *  * @return  */ @RequestLine("POST /feign/provider/post/map") String invokeTest02(@QueryMap Map
   
     map);
   

3. 测试

@Testpublic void test01() {       String response = client.invokeTest01("wade");    System.out.println(response);}@Testpublic void test02() {       Map
   
     map = new HashMap<>();    map.put("name", "wade");    map.put("age", 28);    String response = client.invokeTest02(map);    System.out.println(response);}
   

[PostControllerClient#invokeTest01] ---> POST http://localhost:8001/feign/provider/post?name=wade HTTP/1.1[PostControllerClient#invokeTest01] ---> END HTTP (0-byte body)[PostControllerClient#invokeTest01] <--- HTTP/1.1 200 (163ms)[PostControllerClient#invokeTest01] connection: keep-alive[PostControllerClient#invokeTest01] content-length: 4[PostControllerClient#invokeTest01] content-type: text/plain;charset=UTF-8[PostControllerClient#invokeTest01] date: Sat, 20 Mar 2021 11:22:09 GMT[PostControllerClient#invokeTest01] keep-alive: timeout=60[PostControllerClient#invokeTest01] [PostControllerClient#invokeTest01] wade[PostControllerClient#invokeTest01] <--- END HTTP (4-byte body)wade[PostControllerClient#invokeTest02] ---> POST http://localhost:8001/feign/provider/post/map?name=wade&age=28 HTTP/1.1[PostControllerClient#invokeTest02] ---> END HTTP (0-byte body)[PostControllerClient#invokeTest02] <--- HTTP/1.1 200 (3057ms)[PostControllerClient#invokeTest02] connection: keep-alive[PostControllerClient#invokeTest02] content-length: 19[PostControllerClient#invokeTest02] content-type: text/plain;charset=UTF-8[PostControllerClient#invokeTest02] date: Sat, 20 Mar 2021 11:20:05 GMT[PostControllerClient#invokeTest02] keep-alive: timeout=60[PostControllerClient#invokeTest02] [PostControllerClient#invokeTest02] {   name=wade, age=28}[PostControllerClient#invokeTest02] <--- END HTTP (19-byte body){   name=wade, age=28}

2 body参数

先说明一下，不引入其他依赖，feign不支持表单提交。这里先演示json数据提交

2.1 演示

1. 服务提供者

/** * 测试Body:json */@PostMapping("/post/body")public String test03(@RequestBody User user) {       return user.toString();}

package study.wyy.feign.model;import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONPObject;import lombok.Data;import lombok.ToString;import java.io.Serializable;/** * @author: wyaoyao * @date: 2020-12-17 13:17 * @description: */@Data@ToStringpublic class User implements Serializable {       private String name;    /**     * 年龄     */    private Integer age;}

2. feign客户端

/** * 测试josn * * @return */@RequestLine("POST /feign/provider/post/body")@Body("{body}")@Headers({   "content-type:application/json"})String invokeTest03(@Param("body") User user);

3. 测试

@Testpublic void test03() {       User user = new User();    user.setAge(13);    user.setName("Wade");    String response = client.invokeTest03(user);    System.out.println(response);}

测试报错

[PostControllerClient#invokeTest03] Content-Length: 23[PostControllerClient#invokeTest03] content-type: application/json[PostControllerClient#invokeTest03] [PostControllerClient#invokeTest03] User(name=Wade, age=13) # 请求数据[PostControllerClient#invokeTest03] ---> END HTTP (23-byte body)[PostControllerClient#invokeTest03] <--- HTTP/1.1 400 (59ms)[PostControllerClient#invokeTest03] connection: close[PostControllerClient#invokeTest03] content-type: application/json[PostControllerClient#invokeTest03] date: Sat, 20 Mar 2021 13:13:37 GMT[PostControllerClient#invokeTest03] transfer-encoding: chunked[PostControllerClient#invokeTest03] [PostControllerClient#invokeTest03] {   "timestamp":"2021-03-20T13:13:37.062+0000","status":400,"error":"Bad Request","message":"JSON parse error: Unrecognized token 'User': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false'); nested exception is com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'User': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false')\n at [Source: (PushbackInputStream); line: 1, column: 6]","path":"/feign/provider/post/body"}[PostControllerClient#invokeTest03] <--- END HTTP (495-byte body)feign.FeignException$BadRequest: status 400 reading PostControllerClient#invokeTest03(User)

报了400的错误，JSON parse error；

日志中打印的请求数据是：User(name=Wade, age=13)，默认调用的是User的toString方法，但是发现这样数据就不是个json数据了

既然知道了原因了，最简单的解决方法就是重写user的toString方法，返回json格式的数据

@Overridepublic String toString() {      String s = JSON.toJSONString(this);   return s;}

再测试，发现没有问题：

[PostControllerClient#invokeTest03] ---> POST http://localhost:8001/feign/provider/post/body HTTP/1.1[PostControllerClient#invokeTest03] Content-Length: 24[PostControllerClient#invokeTest03] content-type: application/json[PostControllerClient#invokeTest03] [PostControllerClient#invokeTest03] {   "age":13,"name":"Wade"} # 此时请求数据就是json格式数据[PostControllerClient#invokeTest03] ---> END HTTP (24-byte body)[PostControllerClient#invokeTest03] <--- HTTP/1.1 200 (37ms)[PostControllerClient#invokeTest03] connection: keep-alive[PostControllerClient#invokeTest03] content-length: 23[PostControllerClient#invokeTest03] content-type: text/plain;charset=UTF-8[PostControllerClient#invokeTest03] date: Sat, 20 Mar 2021 13:18:55 GMT[PostControllerClient#invokeTest03] keep-alive: timeout=60[PostControllerClient#invokeTest03] [PostControllerClient#invokeTest03] User(name=Wade, age=13)[PostControllerClient#invokeTest03] <--- END HTTP (23-byte body)User(name=Wade, age=13)

2.2 API讲解

2.2.1 Body注解

该注解作用于方法上，其定义了一个类似于UriTemplate和HeaderTemplate的Template。其中的表达式也使用了@Param注解中的值进行解析。

Body template遵循以下规则：

• 无法解析的表达式将会被省略

• 必须设置Content-Type请求头参数

测试：必须设置Content-Type请求头参数，去掉设置header的代码

@RequestLine("POST /feign/provider/post/body")@Body("{body}")String invokeTest03(@Param("body") User user);

在测试，发现出现415错误

feign.FeignException$UnsupportedMediaType: status 415 reading PostControllerClient#invokeTest03(User)

2.2.2 Headers注解

@Target({   METHOD, TYPE})@Retention(RUNTIME)public @interface Headers {     String[] value();}

能标注在类上和方法上。用于传请求头，使用起来比较简单，形如这样即可：

@Headers({   "Accept:*/*", "Accept-Language:zh-cn"})

唯一注意的一点：k-v使用的是冒号连接，而不是=。

3 body和url同时参数

1. 服务提供者

@PostMapping("/post/bodyAndUrl")public String test04(@RequestParam Map
   
     map,@RequestBody User user) {       return map.toString();}
   

2. feign客户端

@RequestLine("POST /feign/provider/post/bodyAndUrl")@Body("{body}")@Headers({   "content-type:application/json"})String invokeTest04(@QueryMap Map
   
     map,@Param("body") User user);
   

3. 测试

@Testpublic void test04() {       User user = new User();    user.setAge(13);    user.setName("Wade");    Map
   
     map = new HashMap<>();    map.put("name", "kobe");    map.put("age", 28);    String response = client.invokeTest04(map,user);    System.out.println(response);}
   

在服务提供者的controller 中打个断点

当然观察feign的日志输出，也可以看到数据正确封装

[PostControllerClient#invokeTest04] ---> POST http://localhost:8001/feign/provider/post/bodyAndUrl?name=kobe&age=28 HTTP/1.1 # url上正确带有参数[PostControllerClient#invokeTest04] Content-Length: 24[PostControllerClient#invokeTest04] content-type: application/json[PostControllerClient#invokeTest04] [PostControllerClient#invokeTest04] {   "age":13,"name":"Wade"} # 请求体中也是带有了json格式的数据[PostControllerClient#invokeTest04] ---> END HTTP (24-byte body)[PostControllerClient#invokeTest04] <--- HTTP/1.1 200 (34ms)[PostControllerClient#invokeTest04] connection: keep-alive[PostControllerClient#invokeTest04] content-length: 19[PostControllerClient#invokeTest04] content-type: text/plain;charset=UTF-8[PostControllerClient#invokeTest04] date: Sat, 20 Mar 2021 13:29:35 GMT[PostControllerClient#invokeTest04] keep-alive: timeout=60[PostControllerClient#invokeTest04] [PostControllerClient#invokeTest04] {   name=kobe, age=28}[PostControllerClient#invokeTest04] <--- END HTTP (19-byte body){   name=kobe, age=28}

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