java - char[] 上的流写入器不起作用

Question

我有以下代码，但是当我检查输出文件时，char[] cc 似乎没有被写入。谁能告诉我出了什么问题吗？

import java.io.*;

class Test {
  public static void main(String[] args) {
    System.out.printf("start of main\n");
    char[] cc = new char[300];
    try {
      String s = "this is a test.";
      System.arraycopy(s.toCharArray(), 0, cc, 0, s.length());
      System.out.printf("cc = %s\n", new String(cc));
      String filename = "tst.data";
      DataOutputStream ostream = new DataOutputStream(new FileOutputStream(filename));
      OutputStreamWriter writer = new OutputStreamWriter(ostream);
      writer.write(cc, 0, 300);
      ostream.close();

      DataInputStream istream = new DataInputStream(new FileInputStream(filename));
      InputStreamReader reader = new InputStreamReader(istream);
      char[] newcc = new char[300];
      reader.read(newcc, 0, 300);
      istream.close();

      System.out.printf("newcc = %s\n", new String(newcc));
    } catch (Exception e) {
      System.out.printf("Exception - %s\n", e);
    }
  }
}

Answer 1

您需要关闭最外面的 I/O 包装器。

替换

ostream.close();

由

writer.close();

<小时/>

与具体问题无关，这些 DataOutputStream 和 DataInputStream 包装器在此上下文中是不必要的。删除它们。最后，您应该在finally block 中关闭流。另请参阅此相关问题:Do I have to close FileOutputStream which is wrapped by PrintStream?