Java File IO

Java File IO

~主要介绍四个类 InputStream OutputStream FileReader FileWriter~

InputStream （字节流读取File）

 public static void main(String[] args) throws IOException {
       String filePath = "D:\\Javaideaporject\\JavaBaseSolid8\\File\\test.txt";
       FileInputStream fileInputStream = new FileInputStream(filePath);

       int read;
		//如果读到的是-1就说明没有了 读完了
       while ((read = fileInputStream.read())!= -1)
       {
           System.out.print((char)read);
       }

   }

OutputStream（字节流写入File）

public static void main(String[] args) throws IOException {
     String filePath = "D:\\Javaideaporject\\JavaBaseSolid8\\File\\test.txt";
     FileOutputStream fileOutputStream = new FileOutputStream(filePath,true);

      String outPut = "sadfasd";
      fileOutputStream.write(outPut.getBytes());

      fileOutputStream.close();

  }

FileReader（字符流读取File）

 public static void main(String[] args) throws IOException {
      String filePath = "D:\\Javaideaporject\\JavaBaseSolid8\\File\\test.txt";

      FileReader fileReader = new FileReader(filePath);

      int readLean = 0; //读取的字符串长度

      char[] charBuf = new char[8];

      while ((readLean = fileReader.read(charBuf)) != -1)
      {
          System.out.print(new String(charBuf, 0, readLean));
      }
  }

注：这个方法可以读取汉字

 public static void main(String[] args) throws IOException {

        String filePath = "D:\\Javaideaporject\\JavaBaseSolid8\\File\\test.txt";

        FileReader fileReader = new FileReader(filePath);

        int read = 0;

        while ((read = fileReader.read()) != -1)
        {
            System.out.print((char)read);
        }
    }

注：这个方法效率低

FileWriter（字符流写入File）

public static void main(String[] args) throws IOException {

        String filePtah = "D:\\Javaideaporject\\JavaBaseSolid8\\File\\test.txt";

        FileWriter fileWriter = new FileWriter(filePtah, true); //加true是追加 不加是覆盖

        String write = "哈哈哈";

        fileWriter.write(write.toCharArray()); 
        //write(int)
        //write(char[])
        //write(char[], off, len)
        //write(sring)
        //write(string,off,len) 

        fileWriter.close(); //一定要关闭 不然的话写不进去

 }