尝试阻止导致Stream关闭的IOException

时间:2014-05-12 18:01:23

标签: java try-catch inputstream

我的问题是关于这个例外

java.io.IOException: Stream closed
java.util.zip.InflaterInputStream.ensureOpen(InflaterInputStream.java:67)
java.util.zip.InflaterInputStream.read(InflaterInputStream.java:142)
java.io.FilterInputStream.read(FilterInputStream.java:107)
com.avnet.css.servlet.PartNotificationFileServlet.doGet(PartNotificationFileServlet.java:51)
javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

所以我们最近升级了Java 7的代码,我们必须为ZipFile声明实现一个try块。这似乎导致输入流关闭,而在没有尝试阻止之前它没有。在块之前声明它时,不确定我理解为什么。任何人都可以解释或提供解决方案吗?

    String uri = req.getRequestURI();
    String[] tokens = uri.split("/");
    String folder = tokens[tokens.length - 2];//req.getParameter("folder");
    String filename = tokens[tokens.length - 1];req.getParameter("filename");
    Properties properties = new CSSProperties();
    InputStream inputStream = null;
    if(!folder.contains("_AVT")){
        //below is the new try block, when the declaration inside the parenthesis is on its own, instead of inside try, it works fine.  
        try (ZipFile docsZip = new ZipFile(new File(properties.getProperty(PCN_DIR) + File.separator + folder + File.separator + "Documents.zip"))) {
            ZipEntry entry = docsZip.getEntry(filename);
            if (entry != null)                              
                inputStream = docsZip.getInputStream(entry);
        }
    }
    else{
        String decodedFileName = URLDecoder.decode(filename, "UTF-8");
        File file = new File(properties.getProperty(PCN_DIR) + File.separator + folder + File.separator + decodedFileName);
        if(file.exists())
            inputStream = new FileInputStream(file);
    }
    if(inputStream != null){
        resp.setHeader("Content-Type", MimetypesFileTypeMap.getDefaultFileTypeMap().getContentType(filename));
        ServletOutputStream out = resp.getOutputStream();
        byte[] buffer = new byte[2048];
        int read;
        while ((read = inputStream.read(buffer)) > 0) //this is line 51, where the error occurs
            out.write(buffer, 0, read);
        inputStream.close();
        out.close();
    }

2 个答案:

答案 0 :(得分:1)

这是ZipFile#close中记录的行为:

  

关闭此ZIP文件将关闭先前通过getInputStream方法调用返回的所有输入流。

(Java 7 try-with-resources语句在块结束时自动调用close。)

答案 1 :(得分:1)

在当前代码中,您使用的是try-with-resources statement,因此只要ZipFile docsZip完成,您的try就会关闭。

当您将docsZip的声明置于try之内时,它将不会被关闭(请注意,这应该在out.close()之后的某处完成。