Question

我正在使用JERSEY 1.8。当我的函数正常运行时它运行正常。但如果出现异常，则会抛出错误：

com.sun.jersey.api.MessageException: A message body writer for Java class java.util.HashMap, and Java type class java.util.HashMap, and MIME media type application/octet-stream was not found.

我尝试了所有解决方案，但它不会消失。

JAVA课程：

@GET
@Path("/{programId}/export")
public Response exportProgramData(@PathParam(PROGRAM_ID) String programId, @Context HttpServletRequest request) {
    ResponseBuilder respBuilder = null;
    Map<String, Object> response = new HashMap<String, Object>();
    try {

        String programResponse = programsFacade.getProgramReportAsCSV(programId, userId);
        if (programResponse != null) {
            String csvFileName = programsFacade.buildFileNameForReport(programId, userId) + CSV_EXTN;
            respBuilder = Response.ok().entity(new ByteArrayInputStream(programResponse.getBytes()));
            respBuilder.header(HTTP.CONTENT_TYPE, CONTENT_CSV_TYPE);
            respBuilder.header(CONTENT_DISPOSITION, "attachment; filename=\"" + csvFileName + "\"");
            NewCookie downloadCookie = new NewCookie("fileDownload", "true", "/", null, "no comment", 1073741823,
                    false);
            respBuilder.cookie(downloadCookie);
            logger.info(LOGGER_PREFIX + "Exported program response for program: " + programId);
        } else {
            String message = "There was an error while getting the program response.";
            logger.error(LOGGER_PREFIX + message);
            respBuilder = Response.ok().entity(message);
            respBuilder.header(HTTP.CONTENT_TYPE, MediaType.TEXT_PLAIN);
            NewCookie downloadCookie = new NewCookie("fileDownload", "false", "/", null, "no comment", 1073741823,
                    false);
            respBuilder.cookie(downloadCookie);
        }
    } catch (WorkflowManagerException wme) {
        response.put(SUCCESS, false);
        response.put(HTTP_STATUS, WfManagerUtil.getResponseErrorCode(wme).getStatusCode());
        response.put(MESSAGE, wme.getMessage());
        throw new WebApplicationException(Response.status(WfManagerUtil.getResponseErrorCode(wme)).entity(response)
                .build());
    }catch (Exception ex) {
        String message = "There was an error while getting the program response.";
        logger.error(LOGGER_PREFIX + message, ex);
        respBuilder = Response.ok().entity(message);
        respBuilder.header(HTTP.CONTENT_TYPE, MediaType.TEXT_PLAIN);
        NewCookie downloadCookie = new NewCookie("fileDownload", "false", "/", null, "no comment", 1073741823,
                false);
        respBuilder.cookie(downloadCookie);
    }
    return respBuilder.build();
}

POM：

   <dependency>
       <dependency>
        <groupId>org.json</groupId>
        <artifactId>json</artifactId>
        <version>20080701</version>
    </dependency>

    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jackson-provider</artifactId>
        <version>3.0.5.Final</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.2.4</version>
    </dependency>

    <!-- REST Dependency -->
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-server</artifactId>
        <version>1.8</version>
        <!-- <scope>provided</scope> -->
    </dependency>
   n is provided by velocity dep but is not available as artifact -->
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-json</artifactId>
        <version>1.8</version>
        <!-- <scope>provided</scope> -->
    </dependency>

    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-core</artifactId>
        <version>1.8</version>
        <!-- <scope>provided</scope> -->
    </dependency>

如果出现任何WorkflowManagerException，它只会抛出此错误。

请帮忙

Answer 1

尝试给予

respBuilder = Response.ok（）。entity（new String（＆＃34;获取程序响应时出错。＆＃34;））;

在异常捕获

中

Answer 2

假设您希望将HashMap序列化为JSON ...

如果客户端未设置Accept: application/json标头，则Jersey无法知道要将HashMap序列化的媒体类型。因此，它默认尝试序列化为application/octet-stream。并且没有该媒体类型的作者HashMap。您需要通过在响应中设置媒体类型来告诉Jersey

Response errorResponse = Response.status(..)
                                  .entity(response)
                                  .type("application/json")
                                  .build();
throw new WebApplicationException(errorResponse);

还要确保在web.xml中配置jersey-json以使用Jackson

<init-param>
    <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
    <param-value>true</param-value>
</init-param>

抛出WebApplicationException时出错：com.sun.jersey.api.MessageException：找不到Java类java.util.HashMap的消息体编写器

2 个答案: