File的读取和写入操作 java

1、文件的读取操作

 File file = new File(fileName);
	        BufferedReader reader = null;
	        try {
	            System.out.println("以行为单位读取文件内容，一次读一整行：");
	            reader = new BufferedReader(new FileReader(file));
	            String tempString = null;
	            int line = 1;
	            // 一次读入一行，直到读入null为文件结束
	            while ((tempString = reader.readLine()) != null) {
	                // 显示行号
	            	if(tempString.trim().equals(""))
	            		fw.write(tempString+"\r\n");
	            	else if(tempString.indexOf("-")>-1)
	                	fw.write(tempString+"\r\n");
	                else
	                	fw.write(tempString+"→"+"\r\n");
	                	
	            }
	            reader.close();

如遇读取乱码可以改成

 File file = new File("D:\\eee.txt");
	        try {
	            System.out.println("以行为单位读取文件内容，一次读一整行：");
	            FileInputStream fileInputStream = new FileInputStream(file);  
	            InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "GBK");  
	            BufferedReader br = new BufferedReader(inputStreamReader); 
	            String tempString = null;
	            int line = 1;
	            // 一次读入一行，直到读入null为文件结束
	            while ((tempString = br.readLine()) != null) {
	               if(tempString.length() == 1) name1.add(tempString);
	               else if(tempString.length() == 2) name2.add(tempString);
	               else if(tempString.length() == 3) name3.add(tempString);
	               else if(tempString.length() == 4) name4.add(tempString);
	               else if(tempString.length() == 5) name5.add(tempString);
	               else if(tempString.length() == 6) name6.add(tempString);
	               else name7.add(tempString);
	                	
	            }
	            br.close();
	        }catch (Exception e) {
			}

 

 

2、文件的写入操作

File f = new File("liufen.txt");
		if(!f.exists())
			f.createNewFile();
		FileWriter fw = new FileWriter(f,true);
		for(int k=0;k<carInfo.size();k++){
			fw.write(carInfo.get(k).getCar().get(6)+"\r\n");
		}
		fw.flush();
		fw.close();