• 授权服务器目标接口

 @RequestMapping(
        value = {"/oauth/token"},
        method = {RequestMethod.POST}
    )
    public ResponseEntity<OAuth2AccessToken> postAccessToken(Principal principal, @RequestParam Map<String, String> parameters){
...
}

• 自定义按照通常的方式编写feign client

    /**
     * 获取jwt 对象
     *
     * @param parameters
     * @return
     * @throws HttpRequestMethodNotSupportedException
     */
    @RequestMapping( value = "/oauth/token",method = RequestMethod.POST)
    ResponseEntity<OAuth2AccessToken> postAccessToken(@RequestBody MultiValueMap<String, String> parameters);

• 此时会出现反序列化错误
  Resolved [org.springframework.http.converter.HttpMessageNotReadableException: Invalid JSON input: Cannot deserialize instance of java.util.ArrayList<java.lang.Object>out of VALUE_STRING token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance ofjava.util.ArrayList<java.lang.Object> out of VALUE_STRING token at [Source: (PushbackInputStream); line: 2, column: 17] (through reference chain: org.springframework.util.LinkedMultiValueMap["username"])]

• feign client接口需改为使用 String类型接收，测试发现Object也可以接收；

 /**
     * 获取jwt 对象
     *
     * @param parameters
     * @return
     * @throws HttpRequestMethodNotSupportedException
     */
    @RequestMapping( value = "/oauth/token",method = RequestMethod.POST)
    String postAccessToken(@RequestBody MultiValueMap<String, String> parameters);