Java-文件输入输出演示（字符流）

package cn.hncu.IO.cahr;

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileReaderWriterDemo {

public static void main(String[] args) {

//      readFromFile();//从文件中读
//      write2File();//从写入文件中
copyFile();//把信息从文件中写入到另一个文件中
}

private static void copyFile() {

FileReader fr=null;
FileWriter fw=null;
char buf[]=new char[10];
try {
fr=new FileReader("d:\\a.txt");
fw=new FileWriter("d:\\b.txt");
int len=-1;
while((len=fr.read(buf))!=-1){
fw.write(buf,0,len);
}

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
if(fr!=null){
fr.close();
}
if(fw!=null){
fw.close();
}
} catch (IOException e) {
throw new RuntimeException("file cant close");
}
}

}

private static void write2File() {

try {
FileWriter fw=new FileWriter("char.dat");
fw.write("sdggdf瑞雨ssgfh");
//          fw.flush();//字符流中带缓存，要记得刷缓存
fw.close();//带有刷缓存的功能
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

private static void readFromFile() {

try {
FileReader fr=new FileReader("char.dat");
char buf[]=new char[10];
int len=-1;
while((len=fr.read(buf))!=-1){
String str=new String(buf);
System.out.println(str);
}
fr.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}