我在我的项目中使用 Jasper Reports 来生成多种格式的报告。尽管所有代码示例都运行良好,但我遇到了一个概念问题。
我编写了这个简单的代码,它在浏览器中生成 PDF 作为下载选项:
@GET
@Path("/basicdbreport")
@Produces("application/pdf")
public Response basicDbReport(@Context ServletContext context,
@Context HttpServletResponse response) throws JRException,
IOException {
Connection connection = null;
byte[] reportBytes = null;
String reportName = "firstsqlexample";
File file = new File(path + reportName + JASPER_EXTENSION);
// check if compiled report exists
if (!file.exists()) {
compileReport(context.getRealPath(path + reportName + JRXML_EXTENSTION));
}
// input stream for filling the compiled report
InputStream compiledReportStream = context.getResourceAsStream(path
+ reportName + JASPER_EXTENSION);
try {
connection = dataSource.getConnection();
reportBytes = JasperRunManager.runReportToPdf(compiledReportStream,
new HashMap<String, Object>(), connection);
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (reportBytes != null) {
ServletOutputStream outputStream = response.getOutputStream();
outputStream.write(reportBytes);
}
ResponseBuilder restResponse = Response.ok();
restResponse.header("Content-Disposition",
"attachment; filename=firstSQLReport.pdf");
return restResponse.build();
}
代码运行良好,我在浏览器上收到下载提示。然而,当我深入研究 Jasper API 时,我发现了一个方法runReportToPdfStream()方法,它可以为我处理输出流。
新代码如下所示:
@GET
@Path("/basicdbreport")
@Produces("application/pdf")
public Response basicDbReport(@Context ServletContext context,
@Context HttpServletResponse response) throws JRException,
IOException {
ServletOutputStream outputStream = response.getOutputStream();
Connection connection = null;
String reportName = "firstsqlexample";
File file = new File(path + reportName + JASPER_EXTENSION);
// check if compiled report exists
if (!file.exists()) {
compileReport(context.getRealPath(path + reportName + JRXML_EXTENSTION));
}
// input steam to fill complied report
InputStream compiledReportStream = context.getResourceAsStream(path
+ reportName + JASPER_EXTENSION);
try {
connection = dataSource.getConnection();
JasperRunManager.runReportToPdfStream(compiledReportStream, outputStream, new HashMap<String, Object>(), connection);
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
ResponseBuilder restResponse = Response.ok();
restResponse.header("Content-Disposition",
"attachment; filename=firstSQLReport.pdf");
return restResponse.build();
}
代码运行良好,但我没有收到任何下载提示,而是在浏览器上呈现 pdf。响应头如下(在浏览器上):
HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Transfer-Encoding: chunked
Date: Wed, 21 Aug 2013 05:51:42 GMT
代码现在无法提供下载提示的原因是什么?我不是 HTTP 的高手,但我猜是这样的:
restResponse.header("Content-Disposition",
"attachment; filename=firstSQLReport.pdf");
负责下载选项。尽管我确实将它包含在代码中,但它在响应中没有任何位置。请指教。