主要就是分为两种:InputStream与OutputStream、Writer和Reader。主要用到击中类型就是:BufferedReader与BufferedWriter、FileWriter与FileReader、FileInputStream与FileOutputStream、InputStreamReader与OutputStreamWriter。下面是一些示例:
package java_IO;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
public class StreamTest {
//区分字节流和字符流,InputStream和OutputStream等都是字节流,Reader和Writer都是字符流
public static void FileReadToConsole() {
File f=new File("Directory.java");
try {
FileReader fr=new FileReader(f);
int m;
while((m=fr.read())!=-1)//当读取返回值为-1时则读取失败了
System.out.print((char)m);
fr.close();
}
catch(FileNotFoundException e) {
e.printStackTrace();
}
catch(IOException e) {
e.printStackTrace();
}
}
public static void ByteWriteRead() {
String curDir=System.getProperty("user.dir");
File input=new File(curDir+"\\input.txt");
File output=new File("output.txt");
try {
FileInputStream fis=new FileInputStream(input);
FileOutputStream fos=new FileOutputStream(output);
byte[] temp=new byte[80];
int length=fis.read(temp);
System.out.println(length);
fos.write(temp);
fis.close();
fos.close();
}
catch(FileNotFoundException e) {
e.printStackTrace();
}
catch(IOException e) {
}
}
public static void StringReadWrite() {
File f1=new File("input.txt");
File f2=new File("output.txt");
try {
BufferedReader br=new BufferedReader(new FileReader(f1));
BufferedWriter bw=new BufferedWriter(new FileWriter(f2));
//只有BufferedWriter才有newLine用法,FileWriter没有
String temp;
while((temp=br.readLine())!=null) {
bw.write(temp);
bw.newLine();
}
bw.flush();//把缓冲区内容写到文件,如果没有这条语句,输出文件为空。
//使用缓存型流时操作完成后必须加上flush语句。
br.close();
bw.close();
}
catch(FileNotFoundException e) {
e.printStackTrace();
}
catch(IOException e) {
e.printStackTrace();
}
}
public static void ConsoleWriteToFile() {
File consoleIn=new File("ConsoleIn.txt");
try {
FileWriter fw=new FileWriter(consoleIn,true);
//在后面加上true代表只是在文件后面追加,不是重写。当文件不存在的话,就相当于重写了
String temp;
Scanner sc=new Scanner(System.in);
while(!(temp=sc.nextLine()).equals("quit")) {
fw.write(temp);
//FileWriter若是要换行,要用"\r\n"
fw.write("\r\n");
}
fw.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
ByteWriteRead();
StringReadWrite();
ConsoleWriteToFile();
// TODO Auto-generated method stub
}
}