今天我看到了下面的代碼片段，它使用 Java 中的 lambda、可選和函數來呈現特定的端點響應。這個函數、lambda 和那個可選函數的使用在這里真的需要和合理嗎？有什么好處？@RequestMapping(value = "/api/v1/User", produces = "application/json;charset=UTF-8", method = RequestMethod.GET)public String getBySomeAttribute(@RequestParam(value = "someAttribute", required = true) String someAttribute, HttpServletResponse response) { User user = service.getBySomeAttribute(someAttribute); return createResponse(user, response);}private String createResponse(User user, HttpServletResponse response) { String responseBody = maybe((User u) -> { response.setStatus(SC_OK); return toJsonString(userJsonMapper.jsonMapFrom(u)); }).apply(user).orElse(""); setResponseHeaders(response, responseBody.length()); return responseBody;}private Function<User, Optional<String>> maybe(Function<User, String> f) { return (u) -> { String s = null; if (u != null && u.getEnabled()) { s = f.apply(u); } return s != null ? of(s) : Optional.empty(); };}private void setResponseHeaders(HttpServletResponse response, int responseBodySize) { response.setHeader("Content-Length", valueOf(responseBodySize)); response.setHeader("Expires", "1"); response.setHeader("Cache-Control", "no-cache");}
1 回答
鴻蒙傳說
TA貢獻1865條經驗 獲得超7個贊
我幾乎找不到任何理由去做這些。提供的代碼似乎等同于：
@RequestMapping(value = "/api/v1/User", produces = "application/json;charset=UTF-8", method = RequestMethod.GET)
public String getBySomeAttribute(@RequestParam(value = "someAttribute", required = true) String someAttribute,
HttpServletResponse response) {
User user = service.getBySomeAttribute(someAttribute);
return createResponse(user, response);
}
private String createResponse(User user, HttpServletResponse response) {
String responseBody = "";
if(user != null && user.getEnabled()) {
String responseBody = toJsonString(userJsonMapper.jsonMapFrom(user))
response.setStatus(SC_OK);
}
setResponseHeaders(response, responseBody.length());
return responseBody;
}
private void setResponseHeaders(HttpServletResponse response, int responseBodySize) {
response.setHeader("Content-Length", valueOf(responseBodySize));
response.setHeader("Expires", "1");
response.setHeader("Cache-Control", "no-cache");
}
但是上面的內容（在我看來）更容易閱讀、理解和維護。除非 lambda 在其他地方得到廣泛使用，否則我看不出它存在的理由。老實說，即使在其他地方使用它也可能是矯枉過正。
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