在我的 web 服务器应用程序中，我有一个方法，它修改了一个 xml 文档，看起来类似于:

@POST
@Path("somePath")
@Consumes({"application/xml", "application/zip"})
public Response modifyXml() {
    //some processing
}

消耗的zip压缩包包含需要修改的xml文件和一些其他文件。 如何区分消耗的 xml 文件和方法内的存档以及我应该使用哪种方法参数来表示这种消耗的资源？

最佳答案

一种解决方案是只从 InputStream 中读取。您可以将 InputStream 包装在 ZipInputStream 中.使用 ZipInputStream，您可以获得 ZipEntry与 ZipInputStream.getNextEntry() , 然后你可以用 ZipEntry.getName() 得到文件名.然后检查名称 endsWith(".xml").

尽管如此，您将需要使用 application/octet-stream。这是一个简单的例子

@Path("/zip")
public class ZipResource {

    @POST
    @Consumes(MediaType.APPLICATION_OCTET_STREAM)
    public Response postZipFile(InputStream is) throws Exception {
        StringBuilder builder;
        try (ZipInputStream zip = new ZipInputStream(is)) {
            builder = new StringBuilder("==== Data ====\n");
            ZipEntry entry;
            while ((entry = zip.getNextEntry()) != null) {
                String filename = entry.getName();
                if (filename.endsWith(".xml")) {
                    builder.append("name: ").append(entry.getName()).append("\n");
                    String xml = filePartToString(zip, (int) entry.getSize());
                    builder.append("data: ").append(xml).append("\n");
                }
                zip.closeEntry();
            }
        }
        return Response.ok(builder.toString()).build();
    }

    private String filePartToString(InputStream is, int size) throws Exception {
        String xml;
        byte[] buff = new byte[size];
        is.read(buff, 0, size);
        return new String(buff);
    }
}

这是一个测试

@Test
public void testResteasy() throws Exception {
    WebTarget target = client.target(
            TestPortProvider.generateURL(BASE_URI)).path("zip");
    File file = new File("C:/test/test.zip");
    Response response = target.request().post(
            Entity.entity(file, MediaType.APPLICATION_OCTET_STREAM));
    System.out.println(response.getStatus());
    System.out.println(response.readEntity(String.class));
    response.close();
}

在 zip 中使用这些文件

test1.xml
---------
<test1>hello world</test1>

test2.xml
---------
<test2>hello squirrel</test2>

test3.json
----------
{
    "test3":"Hello Girls"
}

我得到以下结果

==== Data ====
name: test1.xml
data: <test1>hello world</test1>
name: test2.xml
data: <test2>hello squirrel</test2>

顺便说一句，如果您可以控制数据的发送方式，您可能还想研究多部分解决方案。您可以在其中设置内容类型，并且可以为每个部分命名，以便于访问。

可以看到Resteasy对multipart的支持here , 和 the required dependency .

更新

如果您必须使用application/zip，则没有对此的标准支持。因此，您需要创建自己的 MessageBodyReader。它可以像包装和返回已经提供的 InputStream

@Provider
@Consumes("application/zip")
public class ZipMessageBodyReader implements MessageBodyReader<ZipInputStream> {

    @Override
    public boolean isReadable(Class<?> type, Type genericType, 
            Annotation[] annotations, MediaType mediaType) {
        return type == ZipInputStream.class;
    }

    @Override
    public ZipInputStream readFrom(Class<ZipInputStream> type, 
            Type genericType, Annotation[] annotations, MediaType mediaType, 
            MultivaluedMap<String, String> httpHeaders, 
            InputStream entityStream) throws IOException, WebApplicationException {

        return new ZipInputStream(entityStream);
    }    
}

然后在您的资源方法中，您可以只使用 ZipInputStream 参数，而不是 InputStream。

@POST
@Consumes("application/zip")
public Response postZipFile(ZipInputStream zip) throws Exception {

在客户端(使用客户端 API)，如果您要使用 application/zip，您当然还需要为 编写一个 MessageBodyWriter >应用程序/zip

更新 2

From Comment: I need my method to be able to consume both a simple xml file and a zip archive which contains the xml file, so I annotate the method something like (pseudo code): "consumes(xml, zip)" and declare a method with the parameter InputStream is; In the method body I then need to determine whether this InputStream is of type xml or a zip archive and want to write something similar to: "if(is of type xml) {then treat is as an xml} else {treat is as a zip archive}. Hopefully now the question is more understandable

我们可以保留您的原始方法签名，同时接受 application/xml 和 application/zip。我们还可以通过注入(inject) HttpHeaders 并从中获取 Content-Type 来检查实际上发送的是哪个。在此基础上，我们将确定如何提取。这是我们如何完成此操作的另一个示例

@Path("/zip")
public class ZipResource {

    @POST
    @Consumes({"application/zip", "application/xml"})
    public Response postZipFile(InputStream is, @Context HttpHeaders headers) throws Exception {
        String contentType = headers.getHeaderString(HttpHeaders.CONTENT_TYPE);
        String returnString = null;

        if (null != contentType) switch (contentType) {
            case "application/xml":
                returnString = readXmlFile(is);
                break;
            case "application/zip":
                returnString = readZipFile(is);
                break;
        }

        return Response.ok(returnString).build();
    }

    private String filePartToString(InputStream is, int size) throws Exception {
        String xml;
        byte[] buff = new byte[size];
        is.read(buff, 0, size);
        return new String(buff);
    }

    private String readXmlFile(InputStream is) {
        StringWriter writer = new StringWriter();
        try {
            IOUtils.copy(is, writer, "utf-8");
        } catch (IOException ex) {
            Logger.getLogger(ZipResource.class.getName()).log(Level.SEVERE, null, ex);
        }
        return writer.toString();
    }

    private String readZipFile(InputStream is) {
        StringBuilder builder = new StringBuilder("==== Data ====\n");
        try (ZipInputStream zip = new ZipInputStream(is)) {
            ZipEntry entry;
            while ((entry = zip.getNextEntry()) != null) {
                String filename = entry.getName();
                if (filename.endsWith(".xml")) {
                    builder.append("name: ").append(entry.getName()).append("\n");
                    String xml = filePartToString(zip, (int) entry.getSize());
                    builder.append("data: ").append(xml).append("\n");
                }
                zip.closeEntry();
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return builder.toString();
    }
}

我们需要一个 MessageBodyReader 来处理 application/zip 类型。上面的那个工作正常，但我们只需要它返回一个 InputStream 而不是 ZipInputStream

@Provider
@Consumes("application/zip")
public class ZipMessageBodyReader implements MessageBodyReader<InputStream> {
    @Override
    public boolean isReadable(Class<?> type, Type genericType, 
            Annotation[] annotations, MediaType mediaType) {
        return type == InputStream.class;
    }

    @Override
    public InputStream readFrom(Class<InputStream> type, 
            Type genericType, Annotation[] annotations, MediaType mediaType, 
            MultivaluedMap<String, String> httpHeaders, 
            InputStream entityStream) throws IOException, WebApplicationException {

        return entityStream;
    }  
}

现在进行测试

@Test
public void testResteasy() throws Exception {
    WebTarget target = client.target(
            TestPortProvider.generateURL(BASE_URI)).path("zip");


    File file = new File("C:/test/test.zip");
    Response response = target.request().post(
            Entity.entity(file, "application/zip"));

    System.out.println(response.getStatus());
    System.out.println(response.readEntity(String.class));
    response.close();

    file = new File("C:/test/test1.xml");
    response = target.request().post(
            Entity.entity(file, "application/xml"));

    System.out.println(response.getStatus());
    System.out.println(response.readEntity(String.class));
    response.close();

}

我们得到以下信息

200
==== Data ====
name: test1.xml
data: <test1>hello world</test1>
name: test2.xml
data: <test2>hello squirrel</test2>

200
<test1>hello world</test1>

注意:对于客户端，我必须实现一个MessageBodyWriter 来处理application/zip 类型。下面是一个简单的实现，只是为了让测试工作。真正的实现需要一些修复

@Provider
@Produces("application/xml")
public class ZipClientMessageBodyWriter implements MessageBodyWriter<File> {

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, 
            Annotation[] annotations, MediaType mediaType) {
        return type == File.class;
    }

    @Override
    public long getSize(File t, Class<?> type, Type genericType, 
            Annotation[] annotations, MediaType mediaType) {
        return -1;
    }

    @Override
    public void writeTo(File t, Class<?> type, Type genericType, 
            Annotation[] annotations, MediaType mediaType, 
            MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) 
            throws IOException, WebApplicationException {

        IOUtils.write(IOUtils.toByteArray(new FileInputStream(t)), entityStream);
    }  
}

....

client.register(ZipClientMessageBodyWriter.class);

您还会注意到在一些示例代码中，我使用了 Apache Commons IOUtils。对不起。我很懒:-)

更新 3

实际上，我们不需要MessageBodyReader。查找阅读器的算法实际上只是默认为 InputStream 阅读器，因为它支持 application/xml，所以它已经返回了 InputStream我们是否有application/zip 的阅读器

关于java - 在 RESTful Web 服务中使用多个资源，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27707724/