使用 Apache Wink 通过 Java REST 服务返回 Excel 文档
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Returning an excel document via a Java REST service with Apache Wink
提问by risingTide
I need to return a Microsoft Excel file from a Java REST service. I'm using WebSphere 8.5 which inherently uses Apache Wink as it's JAX-RS implementation; that's a requirement which I can not change. I am also using Java 7 JDK. Here is the error I'm receiving:
我需要从 Java REST 服务返回 Microsoft Excel 文件。我正在使用 WebSphere 8.5，它本质上使用 Apache Wink，因为它是 JAX-RS 实现；这是我无法改变的要求。我也在使用 Java 7 JDK。这是我收到的错误：
org.apache.wink.server.internal.handlers.FlushResultHandler handleResponse The system could not find a javax.ws.rs.ext.MessageBodyWriter or a DataSourceProvider class for the com.somewhere.else.message.core.BaseResponseMessage type and application/vnd.ms-excel mediaType. Ensure that a javax.ws.rs.ext.MessageBodyWriter exists in the JAX-RS application for the type and media type specified.
org.apache.wink.server.internal.handlers.FlushResultHandler handleResponse 系统找不到 com.somewhere.else.message.core.BaseResponseMessage 类型和应用程序的 javax.ws.rs.ext.MessageBodyWriter 或 DataSourceProvider 类/ vnd.ms-excel 媒体类型。确保在 JAX-RS 应用程序中存在指定类型和媒体类型的 javax.ws.rs.ext.MessageBodyWriter。
Here is my Java Resource class method:
这是我的 Java Resource 类方法：
@GET
@Path("/report")
@Produces("application/vnd.ms-excel")
public Response getReport() {
int fileSize = 0;
byte[] reportByteArray = null;
ResponseBuilder responseBuilder = null;
InputStream report = null;
BaseResponseMessage<InputStream> baseResponseMessage = new
BaseResponseMessage<InputStream>();
Path reportPath = null;
String localPath = "C:/Users/me/Report.xls";
responseBuilder = Response.ok(baseResponseMessage);
responseBuilder.header("Content-Description", "File Transfer");
responseBuilder.header("Content-Disposition", "attachment;
filename=Report.xls");
responseBuilder.header("Content-Transfer-Encoding", "binary");
responseBuilder.header("Connection", "Keep-Alive");
reportPath = Paths.get(localPath);
if (Files.exists(reportPath)) {
if (Files.isReadable(reportPath)) {
reportByteArray = Files.readAllBytes(reportPath);
report = new ByteArrayInputStream(reportByteArray);
}
}
fileSize = report.available();
responseBuilder.header("Content-Length", fileSize);
baseResponseMessage.setPayload(report);
return responseBuilder.build();
}
I do know from looking at the debugger that the path and the excel file are found correctly, and the fileSize is populated correctly as well.
我确实通过查看调试器知道正确找到了路径和 excel 文件，并且 fileSize 也正确填充。
I will gladly provide any more information that is needed. Thank you for your time!
我很乐意提供更多需要的信息。感谢您的时间！
采纳答案by risingTide
The problem was the existence of the BaseResponseMessage. Apparently because I was actually returning the BaseResponseMessage in the Responseobject instead of the actual InputStreamJAX-RS didn't know how to process it since (as the error states) there isn't a MessageBodyWriter or DataSourceProvider specifically associated with that combination. Funny how the error message actually revealed the actual problem had I read it more closely! :p
问题在于 BaseResponseMessage 的存在。显然，因为我实际上是在Response对象中返回 BaseResponseMessage而不是实际的InputStreamJAX-RS 不知道如何处理它，因为（作为错误状态）没有专门与该组合关联的 MessageBodyWriter 或 DataSourceProvider。有趣的是，如果我更仔细地阅读错误消息，它实际上揭示了实际问题！:p
When the code above is modified to remove the BaseResponseMessage and do something like this:
当修改上面的代码以删除 BaseResponseMessage 并执行以下操作时：
responseBuilder = Response.ok(report);
responseBuilder = Response.ok(report);
then it will work just fine.
那么它会工作得很好。
[As an aside, returning an InputStreamis not really a good idea anyway; the code has since been modified to return a StreamingOutputobject.]
[顺便说一句，无论如何，返回InputStream并不是一个好主意；此代码已被修改为返回StreamingOutput对象。]
回答by Arun B Chandrasekaran
I think the problem is on the @Produces annotation. JAX-RS may not know how to handle "application/vnd.ms-excel" by default. You can try using
我认为问题出在@Produces 注释上。默认情况下，JAX-RS 可能不知道如何处理“application/vnd.ms-excel”。您可以尝试使用
@Produces( MediaType.APPLICATION_OCTET_STREAM)
Here is the sample code,
这是示例代码，
- Create a JEE 6 web project
Created an Application Class
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.core.Application;@ApplicationPath("/services/*")
public class MyApplication extends Application {}
Created a REST Resource class,
import java.io.File;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.ResponseBuilder;@Path("/hello")
public class HelloResource {@GET @Path("excel") @Produces(MediaType.APPLICATION_OCTET_STREAM) public Response test2() { File file = new File("C:/users/arun/rest-test.xlsx"); ResponseBuilder rb = Response.ok(file); rb.header("content-disposition", "attachment; filename=rest-test.xlsx"); return rb.build(); }}
- 创建 JEE 6 Web 项目
创建了一个应用程序类
导入 javax.ws.rs.ApplicationPath;
导入 javax.ws.rs.core.Application;@ApplicationPath("/services/*")
public class MyApplication extends Application {}
创建了一个 REST 资源类，
导入 java.io.File;
导入 javax.ws.rs.GET;
导入 javax.ws.rs.Path;
导入 javax.ws.rs.Produces;
导入 javax.ws.rs.core.MediaType;
导入 javax.ws.rs.core.Response;
导入 javax.ws.rs.core.Response.ResponseBuilder;@Path("/hello")
公共类 HelloResource {@GET @Path("excel") @Produces(MediaType.APPLICATION_OCTET_STREAM) public Response test2() { File file = new File("C:/users/arun/rest-test.xlsx"); ResponseBuilder rb = Response.ok(file); rb.header("content-disposition", "attachment; filename=rest-test.xlsx"); return rb.build(); }}
