写文件为什么出现中文乱码

我无意看到

DataOutputStream

的源码.结果发现这段.

    /**
     * Writes out the string to the underlying output stream as a 
     * sequence of bytes. Each character in the string is written out, in 
     * sequence, by discarding its high eight bits. If no exception is 
     * thrown, the counter written is incremented by the 
     * length of s.
     *
     * @param      s   a string of bytes to be written.
     * @exception  IOException  if an I/O error occurs.
     * @see        java.io.FilterOutputStream#out
     */
    public final void writeBytes(String s) throws IOException {
	int len = s.length();
	for (int i = 0 ; i < len ; i++) {
	    out.write((byte)s.charAt(i));
	}
	incCount(len);
    }

out.writer((byte)s.charAt(i));//这个因为英文一个字节就够了,可中文是两个字节,结果我们的中文就在这里被扔掉一半.于是就再输出就乱码了. 相比之下:

 /**
     * Writes a string to the underlying output stream as a sequence of 
     * characters. Each character is written to the data output stream as 
     * if by the writeChar method. If no exception is 
     * thrown, the counter written is incremented by twice 
     * the length of s.
     *
     * @param      s   a String value to be written.
     * @exception  IOException  if an I/O error occurs.
     * @see        java.io.DataOutputStream#writeChar(int)
     * @see        java.io.FilterOutputStream#out
     */
    public final void writeChars(String s) throws IOException {
        int len = s.length();
        for (int i = 0 ; i < len ; i++) {
            int v = s.charAt(i);
            out.write((v >>> 8) & 0xFF); 
            out.write((v >>> 0) & 0xFF); 
        }
        incCount(len * 2);
    }

这个要好一点了,中文就可以真确的被写入了.