休息| @Produces和@Consumes:为什么不都为相同的MIME类型调用它们

问题描述

JAX-REST的新手(球衣1.8版本)

a newbie in JAX-REST (jersey 1.8 impl)

我有一个资源"/hello"类

I have a class for Resource "/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";
    }



}

当我发送带有标头Content-Type : text/html的请求时，我希望同时调用@Produces和@Consumes注释的方法thankYouHTML()和thankYouInputHTML().

when I sent a request with a header Content-Type : text/html, I would expect both the @Produces and @Consumes annotated methods thankYouHTML() and thankYouInputHTML() to be called.

但是只有@Produces thankYouHTML()方法会被调用吗?为什么?为什么不同时调用@Consumes带注释的方法thankYouHInputTML()?

but only the @Produces thankYouHTML() method get called? why? why is not the @Consumes annotated method thankYouHInputTML() also called?

推荐答案

您应该记住:

1. 对于单个请求仅执行一种方法.因此，不可能在单个请求中执行两个(或多个)方法；
2. JAX-RS运行时根据发送到服务器的请求标头值来决定应执行哪种方法.

JAX-RS运行时尝试匹配:

• http方法(GET，POST，...)带有正确的注释(@GET，@POST，...);

• http method (GET,POST, ...) with proper annotation (@GET, @POST,...);

请求路径('/api/something');

http content-type标头(链接)带有正确的@Consumes注释；

http content-type header (link) with proper @Consumes annotation;

http accept标头，带有适当的@Produces注释；

http accept header with propper @Produces annotation;

因此(例如)@Produces注释并不表示带注释的方法会产生某些结果.它表示当请求中包含匹配的accept header时将执行该方法.

So (for example) @Produces annotation does not denote that annotated method produces something. It denotes that method will be executed when matching accept header will be contained in request.

如果您需要RestFull Web服务的更多信息，我建议您阅读以下资源:

If You need more information abou RestFull webservices i advice You to read these resources:

• rfc2616

具有JAX-RS的RESTful Java-作者比尔·伯克

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