java 休息 | @Produces 和 @Consumes ：为什么他们都没有被调用为相同的 MIME 类型
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Rest | @Produces and @Consumes : why dont they both get called for same MIME-type
提问by arthur
a newbie in JAX-REST (jersey 1.8 impl)
JAX-REST 的新手（jersey 1.8 impl）
I have a class for Resource "/hello"
我有一个资源类“/hello”
package com.lbs.rest;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
@Path("/hello")
public class Test {
//-- produces MIME type text/plain
@GET
@Produces(MediaType.TEXT_PLAIN)
public String thankYouTxt(){
System.out.println("thankYouTxt");
return "thankYouTxt\n";
}
//-- consumes MIME type text/plain
@GET
@Consumes(MediaType.TEXT_PLAIN)
public String thankYouInputTxt(){
System.out.println("thankYouInputTxt");
return "thankYouInputTxt";
}
//-- produces MIME type text/html
@GET
@Produces(MediaType.TEXT_HTML)
public String thankYouHTML(){
System.out.println("thankYouHTML");
return "thankYouTxtHTML";
}
//-- consumes MIME type text/html
@GET
@Consumes(MediaType.TEXT_HTML)
public void thankYouInputHTML(){
System.out.println("thankYouInputHTML");
//return "thankYouInputHTML";
}
//-- produces MIME type text/xml
@GET
@Produces(MediaType.TEXT_XML)
public String thankYouXML(){
System.out.println("thankYouXml");
return "<?xml version=\"1.0\"?> <message>thankYouTxt</message>";
}
//-- consumes MIME type text/xml
@GET
@Consumes(MediaType.TEXT_XML)
public String thankYouInputXML(){
System.out.println("thankYouInputXML");
return "thankYouInputXML";
}
}
when I sent a request with a header Content-Type : text/html, I would expect both the @Producesand @Consumesannotated methods thankYouHTML()and thankYouInputHTML()to be called.
当我发送的请求有一个头Content-Type : text/html，我希望无论是@Produces和@Consumes注解的方法thankYouHTML()和thankYouInputHTML()被调用。
but only the @Produces thankYouHTML()method get called? why? why is not the @Consumesannotated method thankYouHInputTML()also called?
但只有@Produces thankYouHTML()方法被调用？为什么？为什么不也调用带@Consumes注释的方法thankYouHInputTML()？
回答by pWoz
You should remember that:
你应该记住：
- Only one method is executed for a single request. So it is impossible to execute two methods (or more) in single request;
- JAX-RS runtime decides which one method should be executed according to request header values sent to to the server.
- 对于单个请求只执行一种方法。所以不可能在单个请求中执行两个（或多个）方法；
- JAX-RS 运行时根据发送到服务器的请求头值决定应该执行哪一种方法。
JAX-RSruntime tries to match:
JAX-RS运行时尝试匹配：
http method (
GET,POST, ...) with proper annotation (@GET,@POST,...);request path (
'/api/something') with the proper@Pathannotation;http
content-typeheader (link) with proper@Consumesannotation;http
acceptheader with propper@Producesannotation;
http 方法 (
GET,POST, ...) 带有适当的注释 (@GET,@POST,...);请求路径 (
'/api/something') 带有正确的@Path注释；带有正确注释的http
content-type标头（链接）@Consumes；accept带有正确@Produces注释的http标头；
So (for example) @Producesannotation does not denote that annotated method produces something. It denotes that method will be executed when matching accept headerwill be contained in request.
所以（例如）@Produces注解并不表示注解的方法会产生一些东西。它表示当匹配accept header将包含在请求中时将执行该方法。
If You need more information abou RestFull webservices i advice You to read these resources:
如果您需要有关 RestFull 网络服务的更多信息，我建议您阅读以下资源：
