读写txt

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class WriterOrReaderTxt {
    // 写文件
    public static void writerTxt() {
        BufferedWriter fw = null;
        try {
            File file = new File("D://text.txt");
            fw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true), "UTF-8")); // 指定编码格式，以免读取时中文字符异常
            fw.append("我写入的内容");
            fw.newLine();
            fw.append("我又写入的内容");
            fw.flush(); // 全部写入缓存中的内容
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fw != null) {
                try {
                    fw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    // 读文件
    public static String readTxt() {  
        String filePath = WriterOrReaderTxt.class.getResource("").getPath() + "a.txt"; // 文件和该类在同个目录下
        System.out.println(filePath);
        BufferedReader reader= null ;
        StringBuilder sb = new StringBuilder();  
        String line = null; 
        try {
            reader = new BufferedReader(new InputStreamReader(new FileInputStream(filePath), "UTF-8"));
             while ((line = reader.readLine()) != null) {   
                    sb.append(line + "\r\n");   
                }  
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                reader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        line = sb.toString().substring(0, sb.length()-4);
         System.out.println(line);
        return line;
    }

    public static void main(String[] args) {
        readTxt();
    }
}