将字符串按照utf-8或gb2312编码写入文件，10个字节一行，当字符超过10个字节则放到下一行。

public static void main(String[] args) {

try {

File in = new File("d:/FileTest.txt");

File out = new File("d:/FileTest2.txt");

FileReader fr = new FileReader(in);

FileWriter fw = new FileWriter(out);

// InputStreamReader isr = new InputStreamReader(new FileInputStream(in));

// OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream(out));

BufferedReader br = new BufferedReader(fr);

BufferedWriter bw = new BufferedWriter(fw);

// System.out.println("in-encoding:" + isr.getEncoding());

// System.out.println("out-encoding:" + osw.getEncoding());

// System.out.println(in.length());

int c;

long line;

if(in.length() % 10 == 0) {

line = in.length()/10;

} else {

line = in.length()/10 + 1;

}

// System.out.println(line);

for (int j = 0; j < line; j++) {

for (int i = 0; i < 5 && (c=br.read()) != -1; i++) {

bw.write(c);

}

bw.newLine();

}

br.close();

bw.close();

} catch (Exception e) {

e.printStackTrace();

}

}