Question

private void readIncomingMessage() {
    try {
        StringBuilder builder = new StringBuilder();
        InputStream is = socket.getInputStream();
        int length = 1024;
        byte[] array = new byte[length];
        int n = 0;

        while ((n = is.read(array, n, 100)) != -1) {
            builder.append(new String(array));

            if (checkIfComplete(builder.toString())) {
                buildListItems(builder.toString(), null);
                builder = new StringBuilder();
            }
        }

    } catch (IOException e) {
        Log.e("TCPclient", "Something went wrong while reading the socket");
    }
}

您好，

我想读取每个100字节块的流，将这些字节转换为字符串，然后查看该字符串是否适合某些条件。

但是当我调试时，我发现该构建器的计数为3072 我看到一个字符串（文字,,,,,,,,,,文字,,,,,,,,,,文字）
我怎样才能将文本添加到stringbuilder？

thx：）

 private void readIncomingMessage() {
    try {
        StringBuilder builder = new StringBuilder();
        InputStream is = socket.getInputStream();
        int length = 100;
        byte[] array = new byte[length];
        int n = 0;

        while ((n = is.read(array, 0, length)) != -1) {
            builder.append(new String(array, 0, n));

            if (checkIfComplete(builder.toString())) {
                buildListItems(builder.toString(), null);
                builder = new StringBuilder();
            }
        }

    } catch (IOException e) {
        Log.e("TCPclient", "Something went wrong while reading the socket");
    }
}

这个解决方案对我有用。这个解决方案的任何缺点？

Answer 1

2个问题：

在将字节转换为String时需要使用'n'值。具体来说，使用此String构造函数String(byte[] bytes, int offset, int length)
将字节转换为任意边界上的字符串时，就像您正在做的那样，您可能会损坏多字节字符。如果InputStreamReader并从中读取字符，最好将'is'放在首位。

Answer 2

有关详情，请参阅read(byte[], int, int)，new String(byte[])和new String(byte[], int, int)

的文档

n将保存上次读取操作中读取的字节数 - 而不是总读取的字节数。如果您一次只想读取多达100个字节，则不需要大小为1024的字节数组，100将执行此操作。当您从字节数组创建一个String时，它会使用整个数组（即使只有一半能够通过读取来填充），除非您告诉它要使用的数组部分。这样的事情应该有效，但你仍然可以做出改进：

private void readIncomingMessage() {
  try {
    StringBuilder builder = new StringBuilder();
    InputStream is = socket.getInputStream();
    int length = 100;
    byte[] array = new byte[length];
    int pos = 0;
    int n = 0;

    while (pos != length && ((n = is.read(array, pos, length-pos)) != -1)) {
        builder.append(new String(array, pos, n));
        pos += n;
        if (checkIfComplete(builder.toString())) {
            buildListItems(builder.toString(), null);
            builder = new StringBuilder();
            pos = 0;
        }
    }

} catch (IOException e) {
    Log.e("TCPclient", "Something went wrong while reading the socket");
}

}

从inputstream读取并添加到stringbuilder

2 个答案: