將請求封包轉換為Java物件
將Java物件轉換為回應訊息
getSupportedMediaTypes：取得支援的MediaType集合（如：text/html，text/plain，application/json）
canRead：判斷是否能讀取（請求）
#read：將請求資料進行格式轉換（canRead方法傳回值為true時調用)
canWrite：判斷是否能寫入（回應）
#write：將回應資料進行格式轉換（canWrite方法傳回值為true時呼叫）
SpringMVC啟動時會自動配置一些HttpMessageConverter（WebMvcConfigurationSupport類別的addDefaultHttpMessageConverters）方法
##來源碼如下：
protected final void addDefaultHttpMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
messageConverters.add(new ByteArrayHttpMessageConverter());
messageConverters.add(new StringHttpMessageConverter());
messageConverters.add(new ResourceHttpMessageConverter());
messageConverters.add(new ResourceRegionHttpMessageConverter());
try {
messageConverters.add(new SourceHttpMessageConverter<>());
}
catch (Throwable ex) {
// Ignore when no TransformerFactory implementation is available...
}
messageConverters.add(new AllEncompassingFormHttpMessageConverter());
if (romePresent) {
messageConverters.add(new AtomFeedHttpMessageConverter());
messageConverters.add(new RssChannelHttpMessageConverter());
}
if (jackson2XmlPresent) {
Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.xml();
if (this.applicationContext != null) {
builder.applicationContext(this.applicationContext);
}
messageConverters.add(new MappingJackson2XmlHttpMessageConverter(builder.build()));
}
else if (jaxb2Present) {
messageConverters.add(new Jaxb2RootElementHttpMessageConverter());
}
if (jackson2Present) {
Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.json();
if (this.applicationContext != null) {
builder.applicationContext(this.applicationContext);
}
messageConverters.add(new MappingJackson2HttpMessageConverter(builder.build()));
}
else if (gsonPresent) {
messageConverters.add(new GsonHttpMessageConverter());
}
else if (jsonbPresent) {
messageConverters.add(new JsonbHttpMessageConverter());
}
if (jackson2SmilePresent) {
Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.smile();
if (this.applicationContext != null) {
builder.applicationContext(this.applicationContext);
}
messageConverters.add(new MappingJackson2SmileHttpMessageConverter(builder.build()));
}
if (jackson2CborPresent) {
Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.cbor();
if (this.applicationContext != null) {
builder.applicationContext(this.applicationContext);
}
messageConverters.add(new MappingJackson2CborHttpMessageConverter(builder.build()));
}
}| 描述 | |
|---|---|
| 負責讀取、寫JSON格式資料（利用Jackson） | |
| #負責讀取、寫入Form表單資料 | |
| 負責讀取、寫入XML格式資料（使用JAXB） | |
| #ByteArrayHttpMessageConverter | |
| StringHttpMessageConverter |
以上是SpringBoot HttpMessageConverter訊息轉換器如何使用的詳細內容。更多資訊請關注PHP中文網其他相關文章！
