File and Buffered Streams

Access Files

• Often use streams for file-based I/O
• Class for each stream type in java.io package
  • FileReader
  • FileWriter
  • FileInputStream
  • FileOutputStream
• The java.io classes are now deprecated
  • Still widely used in code

Buffered Streams

• Direct file access can be inefficient
• Buffered streams can improve efficiency
  • Buffers content in memory
  • Peforms reads/writes in large chunks
  • Reduces underlying stream interaction
• BufferedReader
• BufferedWriter
• BufferedInputStream
• BufferedOutputStream

try(BufferedReader br = new BufferedReader(new FileReader("file1.txt"))){
	int intVal;
	while(intVal = br.read()) >= 0){
		char charVal = (char) intVal;
		// do something with charVal
	}
}

extra benefit of buffered streams: break line support
Line breaks vary across platform

• Unix: \n
• Windows: \r\n

Buffered streams add line break support

• Uses correct value for current platform
• Buffered Writer: generate line breaks with newLine()
• Buffered Reader: line based read with readLine()

// 多行读写模板
void writeData(String[] data) throws IOException{
try(BufferedWriter bw = new BufferedWriter(new FileWriter("data.txt"))){
		for(String d: data){
			bw.write(d);
			bw.newLine();
		} 		
	}
}

void readData() throws IOException{
try(BufferedReader br = new BufferedReader(new FileReader("data.txt"))){
	String inValue;
	while((inValue= br.readLine()) != null){
		System.out.println(inValue);
	}
  }
}

标签：Buffered,File,streams,br,new,Streams,line,data
来源： https://blog.csdn.net/jzhong720/article/details/118441793