我使用springboot框架。我需要加密正文數據（從 json 到加密字符串）。所以我將 ResponseBodyAdvice.java 與 @ControllerAdvice 一起使用，但有一個問題，它總是用雙引號響應加密數據（例如“hello”），我需要只響應 hello 而不是“hello”。@Overridepublic Object beforeBodyWrite(...) {response.getHeaders().set("content-type", "text/plain;charset=UTF-8");//some codes..String result = "hello";return result;}它響應“你好”（我需要不帶雙引號的數據）在控制器類中，它僅響應 hello（不帶雙引號）。請參閱下面的代碼。 @ApiOperation(value = "absdfasdf", produces = "text/plain") @GetMapping("/absd") public String asdfasdf() { return "hello"; }
1 回答
互換的青春
TA貢獻1797條經驗 獲得超6個贊
您需要檢查您的 MessageConverters 以確保 StringMessageConverter 在 MappingJackson2HttpMessageConverter 之前。否則，將選擇 JSON MessageConverter 來序列化字符串并添加額外的雙引號。
@Component
public class MyWebMvcConfigurer implements WebMvcConfigurer {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
// check converter order here
}
}
如以下spring源碼，流程為：
選擇消息轉換器
在 ResponseBodyAdvice 中調用 beforeBodyWrite 方法
轉換消息
AbstractMessageConverterMethodProcessor.java
// choose a message converter
if (genericConverter != null ?
((GenericHttpMessageConverter) converter).canWrite(targetType, valueType, selectedMediaType) :
converter.canWrite(valueType, selectedMediaType)) {
// invoke beforeBodyWrite
body = getAdvice().beforeBodyWrite(body, returnType, selectedMediaType,
(Class<? extends HttpMessageConverter<?>>) converter.getClass(),
inputMessage, outputMessage);
if (body != null) {
Object theBody = body;
LogFormatUtils.traceDebug(logger, traceOn ->
"Writing [" + LogFormatUtils.formatValue(theBody, !traceOn) + "]");
addContentDispositionHeader(inputMessage, outputMessage);
if (genericConverter != null) {
genericConverter.write(body, targetType, selectedMediaType, outputMessage);
}
else {
// convert message
((HttpMessageConverter) converter).write(body, selectedMediaType, outputMessage);
}
}
事實是我們無法更改 ResponseBodyAdvice 中的 MessageConverter。但我們可以自定義一個Dynamic MessageConverter。例如：
public class DynamicMessageConverter implements HttpMessageConverter<Object> {
private final HttpMessageConverter<Object> jsonConverter;
private final HttpMessageConverter<String> stringConverter;
public DynamicMessageConverter(HttpMessageConverter<Object> jsonConverter, HttpMessageConverter<String> stringConverter) {
this.jsonConverter = jsonConverter;
this.stringConverter = stringConverter;
}
@Override
public boolean canWrite(Class clazz, MediaType mediaType) {
return jsonConverter.canWrite(clazz, mediaType) || stringConverter.canWrite(clazz, mediaType);
}
@Override
public List<MediaType> getSupportedMediaTypes() {
List<MediaType> jsonMediaTypes = jsonConverter.getSupportedMediaTypes();
List<MediaType> stringMediaTypes = stringConverter.getSupportedMediaTypes();
List<MediaType> all = new ArrayList<>();
all.addAll(jsonMediaTypes);
all.addAll(stringMediaTypes);
return all;
}
@Override
public void write(Object o, MediaType contentType, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
if (o instanceof String) {
stringConverter.write((String) o, contentType, outputMessage);
} else {
jsonConverter.write(o, contentType, outputMessage);
}
}
@Override
public boolean canRead(Class clazz, MediaType mediaType) {
return false;
}
@Override
public Object read(Class clazz, HttpInputMessage inputMessage) throws HttpMessageNotReadableException {
throw new UnsupportedOperationException();
}
}
然后啟用它
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
StringHttpMessageConverter stringConverter = new StringHttpMessageConverter();
DynamicMessageConverter dynamicMessageConverter = new DynamicMessageConverter(jsonConverter, stringConverter);
converters.add(0, dynamicMessageConverter);
}
直接通過response來寫似乎更簡潔。
@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
response.getHeaders().set("content-type", "text/plain;charset=UTF-8");
//some codes..
String result = "hello";
try (OutputStream stream = response.getBody()) {
stream.write(result.getBytes("utf-8"));
stream.flush();
} catch (IOException e) {
// log ex
}
return null;
}
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