使用Feign实现Form表单提交

原文：http://www.itmuch.com/spring-cloud-sum/feign-form-params/

之前，笔者写了《使用Spring Cloud Feign上传文件》。近日，有同事在对接遗留的Struts古董系统，需要使用Feign实现Form表单提交。其实步骤大同小异，本文附上步骤，算是对之前那篇的补充。

• 添加依赖：

  <dependency>
    <groupId>io.github.openfeign.form</groupId>
    <artifactId>feign-form</artifactId>
    <version>3.2.2</version>
  </dependency>
  <dependency>
    <groupId>io.github.openfeign.form</groupId>
    <artifactId>feign-form-spring</artifactId>
    <version>3.2.2</version>
  </dependency>
  

• Feign Client示例：

  @FeignClient(name = "xxx", url = "http://www.itmuch.com/", configuration = TestFeignClient.FormSupportConfig.class)
  public interface TestFeignClient {
      @PostMapping(value = "/test",
              consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE},
              produces = {MediaType.APPLICATION_JSON_UTF8_VALUE}
              )
      void post(Map<String, ?> queryParam);
  
      class FormSupportConfig {
          @Autowired
          private ObjectFactory<HttpMessageConverters> messageConverters;
          // new一个form编码器，实现支持form表单提交
          @Bean
          public Encoder feignFormEncoder() {
              return new SpringFormEncoder(new SpringEncoder(messageConverters));
          }
          // 开启Feign的日志
          @Bean
          public Logger.Level logger() {
              return Logger.Level.FULL;
          }
      }
  }
  

• 调用示例：

  @GetMapping("/user/{id}")
  public User findById(@PathVariable Long id) {
    HashMap<String, String> param = Maps.newHashMap();
    param.put("username","zhangsan");
    param.put("password","pwd");
    this.testFeignClient.post(param);
    return new User();
  }
  

• 日志：

  ...[TestFeignClient#post] ---> POST http://www.baidu.com/test HTTP/1.1
  ...[TestFeignClient#post] Accept: application/json;charset=UTF-8
  ...[TestFeignClient#post] Content-Type: application/x-www-form-urlencoded; charset=UTF-8
  ...[TestFeignClient#post] Content-Length: 30
  ...[TestFeignClient#post] 
  ...[TestFeignClient#post] password=pwd&username=zhangsan
  ...[TestFeignClient#post] ---> END HTTP (30-byte body)
  

  由日志可知，此时Feign已能使用Form表单方式提交数据。

参考文档

• https://github.com/OpenFeign/feign-form
• https://stackoverflow.com/questions/35803093/how-to-post-form-url-encoded-data-with-spring-cloud-feign