OK，改个名字，只想知道第一题的详细答案，其他我也能说出一二，别鸡鸡爪爪的，没素质

public class WriteFileThread extends Thread {
	
	private File file;
	
	private String fileString="E://javaTest//t.txt";
	
	@Override
	public void run(){
		file = new File(fileString);
		StringBuffer sBuffer = new StringBuffer();
		Scanner scanner;
		try {
			scanner = new Scanner(file);
			while(scanner.hasNextLine()){
				sBuffer.append(scanner.nextLine());
			}
			BufferedWriter bWriter;
			bWriter = new BufferedWriter(new FileWriter(file));
			bWriter.append(sBuffer);
			bWriter.append("\r\n");
			bWriter.append("1234567890");
			bWriter.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
}

public class ReadFileThread extends Thread {
	
	private File file;
	
	private String fileString="E://javaTest//t.txt";
	
	@Override
	public void run(){
		file = new File(fileString);
		try {
			BufferedReader bReader = new BufferedReader(new FileReader(file));
			String temString = null;
				while((temString=bReader.readLine())!=null) {
					System.out.println(temString);
				}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}