java文件操作02--IO读写文件

前面对文件创建进行了解读，本章对文件读写进行解读

传统的IO操作

读取

• FileReader.read();

FileReader reader=new FileReader("F:/text.txt");
int c=0;
char[] buf=new char[1024];
while( (c=fr.read(buf))!=-1 ){
    sout((new String(buf,0,c)));
}

• BufferedReader.readline();

BufferedReader in=new BufferedReader(new FileReader(fileName));
line=in.readLine();
while (line!=null)
{
 System.out.println(line);
 line=in.readLine();
}
in.close();

操作完成后都需要关闭流

写入

• FileWriter实例的方法write( string );

 FileWriter writer=new FileWriter("F:/text.txt");
 writer.write("text\n");
 writer.close();

• BufferedWriter实例的方法write( string );

BufferedWriter out=new BufferedWriter(new FileWriter("F:/text.txt"));
out.write("text");
out.newLine(); 
out.close();

操作完成后都需要关闭流

NIO操作

读取

• //全部读取
  byte[] data    = Files.readAllBytes( Paths.get("F:/text.txt") );
  

• //全部行读取
  List<String> lines = Files.readAllLines(Paths.get("F:/text.txt"));
  

写入

• //写入文件
  Files.write(Paths.get("F:/text.txt"), "text\n".getBytes());
  

• //文件追加
  Files.write(Paths.get("F:/text.txt"), "text\n".getBytes(),StandardOpenOption.APPEND);
  

Files其他方法

InputStream ins = Files.newInputStream(Paths.get("F:/text.txt"));
OutputStream ops = Files.newOutputStream(Paths.get("F:/text.txt"));
Reader reader = Files.newBufferedReader(Paths.get("F:/text.txt"));
Writer writer = Files.newBufferedWriter(Paths.get("F:/text.txt"));