Java基础——IO流(下)

IO流(下)

其他相关流

如图

1.FIle文件类

用于操作文件的类,详情请查看API

2.打印流

1)PrintStream (字节)

2)PrintWriter(字符)

import java.io.BufferedInputStream;import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.PrintStream;import java.io.PrintWriter;class PrintDemo{public static void main(String[] args) throws Exception{//输入//BufferedInputStream cin = new BufferedInputStream(System.in);BufferedReader cin = new BufferedReader(new InputStreamReader(System.in));//字符输出流PrintWriter out = new PrintWriter("a.txt");//字节输出流//PrintStream out = new PrintStream("a.txt");String line = null;while((line = cin.readLine())!=null){out.println(line);out.flush();}out.close();cin.close();}}

3.管道流

import java.io.*;//建议多线程//读取class Read implements Runnable{private PipedInputStream in;Read(PipedInputStream in){this.in = in;}public void run(){try{byte[] buf = new byte[1024];int len = in.read(buf);String s = new String(buf ,0,len);System.out.println(s);in.close();}catch(Exception e){}}}//写入class Write implements Runnable{private PipedOutputStream out;Write(PipedOutputStream out){this.out = out;}public void run(){try{out.write("管道".getBytes());out.close();}catch(Exception e){}}}class PipedIODemo{public static void main(String[] args) throws IOException{PipedInputStream in = new PipedInputStream();PipedOutputStream out = new PipedOutputStream();in.connect(out);Thread t1 = new Thread(new Read(in));Thread t2 = new Thread(new Write(out));t1.start();t2.start();}}

4.序列流(合并流)

import java.io.*limport java.util.*;class SequenceInputStreamDemo{public static void main(String[] args) throws IOException {//File f = new File("e:");//建立文件输入集合Vector<FileInputStream> v = new Vector<FileInputStream>();//输入文件v.add("1.txt");v.add("2.txt");//获取文件Enumeration<FileInputStream> en = v.elements();//合并流SequenceInputStream sis = new SequenceInputStream(en);//合并后文件FileOutputStream fos = new FileOutputStream("4.txt");byte[] buf = new byte[1024];int len = 0;//合并操作while((len = sis.read(buf))!=-1){fos.write(buf,0,len);}fos.close();sis.close();}}

5.对象序列化流

import java.io.*;//准备写入的对象,必须实现Serializable接口,标记接口class Student implements Serializable{public static final long serialVersionUID = 1L;//如果类发生改变,只要ID不变,默认为一个类private String name;transient private int age;//transient参数,有的话,就不写入Student(String name ,int age){this.name = name;this.age = age;}public String toString(){return name+"  "+age;}}class ObjectIODemo{public static void main(String[] args) throws Exception{//读取//ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("Object.txt"));//oos.writeObject(new Student("xiaoming",22));//oos.close();//输入ObjectInputStream ois = new ObjectInputStream(new FileInputStream("Object.txt"));Student p = (Student)ois.readObject();System.out.println(p);ois.close();}}

输入输出重定向

System类中的字段：in，out,是标准输入输出,默认的话是输入时键盘,输出是显示器

System.in的类型是InputSteam

System.out的类型是PrintSteam

1.输入重定向

import java.io.FileInputStream;import java.io.IOException;public class SystemIn {//没处理异常public static void main(String[] args) throws IOException {//重定向输入,从文件输入System.setIn(new FileInputStream("aa.txt"));byte buff[] = new byte [1024];int len = 0;String str = null;while((len=System.in.read(buff))!=-1){str += new String(buff, 0, len);}System.out.println(str);}}

2.输出重定向

import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.PrintStream;public class SystemOut {//没处理异常public static void main(String[] args) throws FileNotFoundException {//设置输出System.setOut(new PrintStream(new FileOutputStream("out.txt")));String str = "测试实验";System.out.println(str);}}

三种键盘录入方式
A:main方法的args接收参数
B:System.in通过BufferedReader进行包装
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
C:Scanner
Scanner sc = new Scanner(System.in);