为什么在这种情况下必须以某种方式关闭ZipOutputStream？

Question

我有两个例子：

范例1：

try (ByteArrayOutputStream baous = new ByteArrayOutputStream();     
    FileOutputStream fouscrx = new FileOutputStream(new File(output, "example"))) {
        try (ZipOutputStream zous = new ZipOutputStream(baous)) {
            for (File file: files) {
                try (FileInputStream fis = new FileInputStream(file)) {
                    ZipEntry zipEntry = new ZipEntry(file.getPath().substring(output.getPath().length() + 1));
                    zous.putNextEntry(zipEntry);
                    byte[] bytes = new byte[2048];
                    int length;
                    while ((length = fis.read(bytes)) >= 0) {
                        zous.write(bytes, 0, length);
                    }
                    zous.closeEntry();
                }
            }
        }
        baous.writeTo(fouscrx);
    } catch (FileNotFoundException ex) {} catch (IOException ex) {}

范例2：

try (ByteArrayOutputStream baous = new ByteArrayOutputStream();
          ZipOutputStream zous = new ZipOutputStream(baous);
       FileOutputStream fouscrx = new FileOutputStream(new File(output, "example"))) {
            for (File file: files) {
                try (FileInputStream fis = new FileInputStream(file)) {
                    ZipEntry zipEntry = new ZipEntry(file.getPath().substring(output.getPath().length() + 1));
                    zous.putNextEntry(zipEntry);
                    byte[] bytes = new byte[2048];
                    int length;
                    while ((length = fis.read(bytes)) >= 0) {
                        zous.write(bytes, 0, length);
                    }
                    zous.closeEntry();
                }
            }
            baous.writeTo(fouscrx);
        } catch (FileNotFoundException ex) {} catch (IOException ex) {}

在 第二个 例子不工作，我想它做的事。我的意思是文件内容不为空，但好像zip文件已损坏。

我想告诉我第一个例子为什么不起作用。

Answer 1

ZipOutputStream
必须在流的末尾执行多项操作以完成zip文件，因此必须正确关闭它。（一般来讲，按照惯例，每个流几乎都
应该 正确关闭。）