Java学习之输入输出流/文件读写

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/liyangxueit/article/details/50868455

周六在学校图书馆实在没有什么事做，敲了一下午的代码，稍微搞懂了点输入输出流与文件读写方面的知识。接下来直接上代码：

package liyangfile;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class Filechuli {
public static void main(String args[]){
    try{
        File fdir=new File("/home/liyang/桌面","liyang.txt");
        String  s="李杨要努力学会it";
        PrintWriter fout=new PrintWriter(new FileWriter(fdir,true));
        fout.println(s);
        fout.close();
    }catch(IOException e){}
}
}

package liyangfile;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public class Liyang1 {

public static void main(String[] args) {
try{
    File f =new File("/home/liyang/桌面","liyang.txt");
    FileReader fr=new FileReader(f);        
    char[] s=new char[50];
    fr.read(s);
    fr.close();
    System.out.println(s);
}catch(IOException e){}
}

}

package liyangfile;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class Liyang2 {

    public static void main(String[] args) {
        try{
        File fl=new File("/home/liyang/桌面","liyang.txt");
        FileInputStream fis=new FileInputStream(fl);
        byte[] bs=new byte[20];
        fis.read(bs);
        fis.close();
        for(int i=0;i<bs.length;i++){
            System.out.print(bs[i]);
        }
        }catch(IOException e){}
    }

}

package liyangfile;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class Liyang3 {

public static void main(String[] args) {        // TODO Auto-generated method stub
try{
    File f=new File("/home/liyang/桌面","liyang.txt");
    FileWriter fw=new FileWriter(f);
    Scanner sc=new Scanner(System.in);
    String s=sc.next();
    sc.close();
   fw.write(s);
   fw.close();
}catch(IOException e){}
}

}

package liyangfile;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;

public class Liyang4 {

    public static void main(String[] args)  {
        try{
        BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
        File f=new File("/home/liyang/桌面");
        String f_array[];
        if(f.exists()&&f.isDirectory()){
            System.out.println(f.getPath()+"目录存在，其内容为");
            f_array=f.list();
            for(int i=0;i<f_array.length;i++){
                System.out.println(f_array[i]);
            }
            File f1=new File("/home/liyang/桌面/ly");
            if(! f1.exists())
                f1.mkdirs();
            System.out.println("再次查看指定目录下的文件");
            f_array=f.list();
            for(int i=0;i<f_array.length;i++){
                System.out.println(f_array[i]);
            }
        }
        System.out.println("请输入该目录下的一个文件名");
        String s=in.readLine();
        File f2=new File(f,s);
        if(f2.isFile())
            System.out.println(f2.getName()+"文件的长度是"+f2.length());
        else
            System.out.println("所指定的不是文件");
        }catch(IOException e){}
        }
}

package liyangfile;
import java.io.IOException;
import java.io.StringReader;
import java.util.Scanner;

public class Liyang5 {
public static void main(String args[]){
//try{
//BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
//String s=in.readLine();
//System.out.println(“您输入的是”+s);
//}catch(IOException e){}
//}
try{
Scanner input=new Scanner(System.in);
String s=input.nextLine().toString();
input.close();
StringReader sin1=new StringReader(s);
System.out.println(“您输入的是”+sin1.read());
sin1.close();
}catch(IOException e){}
}
}

package liyangfile;
import java.io.*;
public class Liyang6 {

    public static void main(String[] args) {
        char ch;
        int chi;
        File mypath=new File("/home/liyang/桌面/ly");
        if(!mypath.exists())
            mypath.mkdirs();
        File myFile=new File(mypath,"ly.txt");
        try{
            FileOutputStream fout=new FileOutputStream(myFile);// TODO Auto-generated method stub
      System.out.println("请输入一个字符串并且以#结尾");
      while((ch=(char)System.in.read())!='#'){
          fout.write(ch);
      }
      fout.close();
      System.out.println("下面是从刚刚写入的文件中读出的数据");
      FileInputStream fin=new FileInputStream(myFile);          
        while((chi=fin.read())!=-1)
            System.out.print((char)chi);
        fin.close();
        }
        catch(FileNotFoundException e ){
            System.err.println(e);
        }
        catch(IOException e){
            System.err.println(e);
        }

    }

}

package liyangfile;
import java.io.*;
public class Liyang7 {

public static void main(String[] args) {

try{
File f=new File(“/home/liyang/桌面/liyang.txt”);
FileInputStream fin=new FileInputStream(f);
int s;
while((s=fin.read())!=-1)
System.out.print((char)s);
fin.close();
}catch(IOException e){}
}

}

package liyangfile;
import java.io.*;
public class Liyang8 {

    public static void main(String[] args) {
try{
    File d=new File("/home/liyang/桌面/liyang.txt");
    FileOutputStream fout=new FileOutputStream(d);
    char ch;
    System.out.println("请输入一串字符串并以#结尾");
    while((ch=(char)System.in.read())!='#')
        fout.write(ch);
    fout.close();
}catch(IOException e){System.err.println(e);}
    }

}
也算忙活了一下，希望有所收获吧！加油，java学习之旅