Question

java 编程

在一个类的main方法中通过键盘输入一串字符，以“#”号作为结束，再将字符串中的小写英文字母改写成在大写，最后将改写好的字符串写入D盘下的file1.txt, 然后将此文件中的内容读取出来显示在屏幕上。

Answer 1

import java.io.*;
import java.util.Scanner;

public class L {
public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("请输入...");
String input = sc.next();

input = input.toUpperCase();
System.out.println(input);

File f=new File("D:\\file1.txt");
try{
f.createNewFile();
System.out.println("创建文件成功\n");

OutputStream out =new FileOutputStream(f);
byte[] ob=input.getBytes();
out.write(ob);
System.out.println("写入成功！");
out.close();

InputStream in=new FileInputStream(f);
byte[] ib=new byte[1024];
int len=in.read(ib);
in.close();
System.out.println("\n读入长度为："+len);
System.out.println("读取内容是：");
System.out.println(new String(ib,0,len));
}catch (Exception e) {
e.printStackTrace();
}
}
}

Answer 2

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

public class drcp {

public static void main(String[] args) throws IOException {
String str = "";
String outString;
if (args.length<=0){
System.out.println("error");
return;
}
for (int i = 0; i < args.length; i++) {
if(args[i].indexOf("#")>=0){
str += args[i].toUpperCase().substring(0,args[i].indexOf("#"));
break;
}else{
str += args[i].toUpperCase()+" ";
}
}
File file = new File("d:\\file1.txt");
if(!file.exists())file.createNewFile();
BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
PrintWriter out = new PrintWriter(file);
out.write(str);
out.flush();
outString = in.readLine();
out.close();
in.close();
System.out.println(outString);

}

}

Answer 3

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