文件写入一行 、读取一行的工具类案例

  java 写入文件一行数据

  java读取文件一行数据

  只是案例代码

 

    /**
     * 判断该坐标是否已经转换
     */
    public static String isRead(String str) {
        
     try {    
         File file = new File("parseLocation.txt");
            if(!file.exists()){
                file.createNewFile();
            }
        BufferedReader br = new BufferedReader(new FileReader(file));// 构造一个BufferedReader类来读取文件
        String line ="";
          while ((line = br.readLine()) != null) {   
              
              if((line.substring(0,line.indexOf(":"))).equals(str)){
                  return line.substring(line.indexOf(":")+1);
              }
            }
          br.close();
        } catch (Exception e) {
            // TODO: handle exception
        }
        
        return "1";        
    }
    
    /**
     * 写入文件
     */
    public static void write(String key,String val) {    
        try {
            if(!"1".equals(isRead(key))){
                return;
            };
            File file = new File("parseLocation.txt");
            if(!file.exists()){
                file.createNewFile();
            }
         FileOutputStream stream = new FileOutputStream(file, true);
            stream.write((key+":"+val+System.getProperty("line.separator")).getBytes());
            stream.flush();        
            stream.close();
        } catch (Exception e) {
            // TODO: handle exception
        }
    }