Clone InputStream

Question

我正试图从InputStream读取数据，这可能是FileInputStream或ObjectInputStream。为了实现这一点，我想克隆流并尝试读取对象，并在出现异常的情况下使用apache commons io将流转换为字符串。

    PipedInputStream in = new PipedInputStream();
    TeeInputStream tee = new TeeInputStream(stream, new PipedOutputStream(in));
    Object body;
    try {
        ObjectInput ois = new ObjectInputStream(tee);
        body = ois.readObject();
    } catch (Exception e) {
        try {
            body = IOUtils.toString(in, Charset.forName("UTF-8"));
        } catch (Exception e2) {
            throw new MarshallerException("Could not convert inputStream");
        }
    }

不幸的是，这不起作用，因为程序在尝试将流in转换为字符串时等待传入数据。

Answer 1

正如Boris Spider已经评论的那样，可以读取整个流，例如到字节数组流，然后在该资源上打开新的流:

    byte[] byteArray = IOUtils.toByteArray(stream);     
    InputStream input1 = new ByteArrayInputStream(byteArray);
    InputStream input2 = new ByteArrayInputStream(byteArray);
    Object body;
    try {
        ObjectInput ois = new ObjectInputStream(input1);
        body = ois.readObject();
    } catch (Exception e) {
        try {
            body = IOUtils.toString(input2, Charset.forName("UTF-8"));
       } catch (Exception e2) {
            throw new MarshalException("Could not convert inputStream");
        }
    }