java utf-8 文件的读写

场景：

将UTF-8编码的模版文件读入内存，然后转换后存储为html文件。

注意点：

utf-8编码的文件开头有3个附加字节：0xEF 0xBB 0xBF

unicode编码的文件开头有2个附加字节：0xFF 0xFE (little endian)，或者0xFE 0xFF(big endian)

ANSI编码则没有附加字节

如果读写不当， 可能得不到预期结果（html会显示为乱码）

读示例：

String readFile(String utf8File) {

Reader streamReader = new InputStreamReader(new FileInputStream(utf8File), "UTF-8");

Reader reader = new BufferedReader(streamReader);

String line = null;

StringBuilder text = new StringBuilder();

while ((line = reader.readLine()) != null) {

text.append(line);

}

reader.close();

return text.toString();

}

写示例：

String template = readFile("c://utf8.template");

String outputFile = "c://utf8.htm";
Writer writer = new PrintWriter(
new OutputStreamWriter(new FileOutputStream(outputFile), "UTF-8"));

template = template.replace("$title$", "UTF-8 read and write");

writer.write(template);
writer.close();