Java BufferedReader、FileReader、FileWriter、PrintWriter

FileReader

FileReader 类从 InputStreamReader 类继承而来。该类按字符读取流中数据。可以通过以下几种构造方法创建需要的对象:
FileReader(File file);
FileReader(FileDescriptor fd);
FileReader(String fileName);

看一段简单的代码

import java.io.*;
public class Filereader{public static void main(String args[])throws IOException{File file = new File("Hello.txt");// create a filefile.createNewFile();// creates a FileWriter ObjectFileWriter writer = new FileWriter(file); // write to the filewriter.write("hello world!\nAre you OK?"); writer.flush();writer.close();// create a FileReader objectFileReader filereader = new FileReader(file); char [] a = new char[50];//read contents from the file to arrayfilereader.read(a); for(char c : a){//print the contents of the array in one characterSystem.out.print(c);}//close the FileReaderfilereader.close();}
}

BufferedReader：

    //path of the fileString pathname = "input.txt"; File filename = new File(pathname); FileInputStream fis = new FileInputStream(filename);//Create a InputStreamreader objectInputStreamReader reader = new InputStreamReader(isr,,"UTF-8");BufferedReader br = new BufferedReader(reader);String line = "";line = br.readLine();//read a line one timewhile (line != null) {line = br.readLine(); }/* 写入Txt文件 */File writename = new File("output.txt");writename.createNewFile(); BufferedWriter out = new BufferedWriter(new FileWriter(writename));out.write("我会写入文件啦\r\n"); out.flush(); out.close(); 

PrintWriter

public class PrintWriter {
    public static void main(String[] args) {try {//open fileFileOutputStream fos=new FileOutputStream("pw.txt");OutputStreamWriter osw=new OutputStreamWriter(fos,"UTF-8");/*** 创建具有自动刷新的PrinterWriter后，每当我们使用println()/print()* 方法写出字符串后，都会自动调用flush()方法* 但是会增加写出次数而降低写出效率*/PrintWriter pw=new PrintWriter(osw, true);pw.println("helloworld");pw.append("Are you OK?");pw.write("Thank you");pw.close();} catch (Exception e) {e.printStackTrace();}}
}

有关更详细的关于java文件操作的方法以后再补充~