codetest

package cn.itcast.iostream;/* * 字符输入流的缓冲区对象 * BuffereReader */import java.io.*;public class BufferedReaderDemo {public static void main(String[] args) throws IOException{//建立字符输入流对象FileReader fr = new FileReader("c:\\buffered.txt");FileWriter fw = new FileWriter("c:\\xxxx.txt");//建立字符输入缓冲区对象BufferedReader bfr = new BufferedReader(fr);//调用缓冲区对象中的readLine()方法，读取一行，并返回字符串String line = null;while((line = bfr.readLine())!=null){fw.write(line);fw.flush();}bfr.close();fw.close();}}

2

package cn.itcast.iostream;/* * 演示字符输出流的缓冲区对象 * BufferedWriter */import java.io.*;public class BufferedWriterDemo {public static void main(String[] args) throws IOException{//使用缓冲区，必须先有输出流对象FileWriter fw = new FileWriter("c:\\buffered.txt");//建立缓冲区对象，传递字符输出流对象BufferedWriter bfw = new BufferedWriter(fw);/* * BufferedWriter{ *   public void close(){ *     fw.close(); *   } * } */bfw.write("abc");bfw.newLine();bfw.write("qqq");bfw.flush();bfw.close();}}

CopyTextDemo

package cn.itcast.iostream;/* * 复制文本文件 * 将C盘中的text.txt文件复制到D盘 */import java.io.*;public class CopyTextDemo {public static void main(String[] args) {//获取开始时间long start = System.currentTimeMillis();//调用复制文件的方法copy_3();//获取结束时间long end = System.currentTimeMillis();System.out.println(end - start);}//复制文本文件，使用缓冲区对象，实现读一行，写一行，写换行private static void copy_3(){//声明两个缓冲区对象的引用变量BufferedReader bfr = null;BufferedWriter bfw = null;try{bfr = new BufferedReader(new FileReader("c:\\abc.txt"));bfw = new BufferedWriter(new FileWriter("d:\\abc.txt"));//读一行，写一行，写换行String line = null;while((line = bfr.readLine())!=null){bfw.write(line);bfw.newLine();bfw.flush();}}catch(IOException e){e.printStackTrace();throw new RuntimeException("复制失败");}finally{try{if(bfw!=null)bfw.close();}catch(IOException e){throw new RuntimeException("文件写入关闭失败");}try{if(bfr!=null)bfr.close();}catch(IOException e){throw new RuntimeException("文件读取关闭失败");}}}//复制文件，读取一个数组，写一个数组，带上异常处理private static void copy_2(){FileReader fr = null;FileWriter fw = null;try{//建立数据源，读取流对象fr = new FileReader("c:\\text.txt");//建立数据目的，输出流对象fw = new FileWriter("d:\\text.txt");//开始循环读取源文件//读取数组，写数组char[] buf = new char[1024];int len = 0 ;while((len = fr.read(buf))!=-1){//读一个，写一个fw.write(buf,0,len);}}catch(IOException e){e.printStackTrace();throw new RuntimeException("复制失败");}finally{try{if(fw!=null)fw.close();}catch(IOException e){throw new RuntimeException("文件写入关闭失败");}try{if(fr!=null)fr.close();}catch(IOException e){throw new RuntimeException("文件读取关闭失败");}}}//复制文件，第一个字符，写一个字符，带上异常处理private static void copy_1(){//声明变量，字符输入流(数据源)，字符输出流(数据目的)FileReader fr = null;FileWriter fw = null;try{//建立数据源，读取流对象fr = new FileReader("c:\\text.txt");//建立数据目的，输出流对象fw = new FileWriter("d:\\text.txt");//开始循环读取源文件int len = 0 ;while((len = fr.read())!=-1){//读一个，写一个fw.write((char)len);}}catch(IOException e){e.printStackTrace();throw new RuntimeException("复制失败");}finally{try{if(fw!=null)fw.close();}catch(IOException e){throw new RuntimeException("文件写入关闭失败");}try{if(fr!=null)fr.close();}catch(IOException e){throw new RuntimeException("文件读取关闭失败");}}}}

FileReaderDemo

package cn.itcast.iostream;/* * 字符流读取文件 */import java.io.*;public class FileReaderDemo implements Serializable{public static void main(String[] args)throws IOException {//建立字符读取流对象FileReader fr = new FileReader("c:\\demo.txt");//调用FileReader类的父类的方法read,读取单个字符//如果读取到了有效字符，read方法，返回ASCII值，如果读取到了文件的末尾，返回-1//循环的读取文件int len = 0 ;while((len = fr.read())!=-1){System.out.print((char)len);}fr.close();}}

FileReaderDemo1

package cn.itcast.iostream;/* * 读取数组 */import java.io.*;public class FileReaderDemo1 {public static void main(String[] args) throws IOException{//建立输入流的对象FileReader fr = new FileReader("c:\\demo.txt");//读取文件，文件中的字符，存储到字符数组char[] buf = new char[1024];// 2kb//read(buf)int类型的返回值int len = 0 ;while((len = fr.read(buf))!=-1){//将数组变成字符串打印System.out.println(len);System.out.print(new String(buf,0,len));}/*len = fr.read(buf);System.out.println("len="+len);//2//将数组变成字符串打印System.out.println(new String(buf));//ablen = fr.read(buf);System.out.println("len="+len); //2System.out.println(new String(buf));//cdlen = fr.read(buf);System.out.println("len="+len); // 1System.out.println(new String(buf)); //edlen = fr.read(buf);System.out.println("len="+len); // 1System.out.println(new String(buf)); //ed*/fr.close();}}

FileWriterDemo2

package cn.itcast.iostream;/* * 续写 *  * 写字符数据 */import java.io.*;public class FileWriterDemo2 {public static void main(String[] args) throws IOException{FileWriter fw = new FileWriter("c:\\demo.txt");//定义一个字符数组char[] ch = {'a','c','d','e','子','符','流'};fw.write(ch,0,ch.length);fw.write("\r\n");fw.write(ch, 0, ch.length);fw.flush();fw.close();}}