Java文件操作

[傻熙Ta爸]

（1）计算这篇短文的字符数（含空白）共有多少？
（2）若不含空白，这篇短文共有多少个字符？
（3）统计这篇短文用了多少个单词“to”。
（4）将这篇短文内所有大写字母改成小写，并将更改后的短文写到文本文件”joke.txt” 里。
There was an American couple who had no children, so they wanted to adopt a child. Finally, an orphanage contacted them, saying, "We have a baby for adoption.It's a Russian orphan." The couple was delighted and went to bring the baby home.
On the way home, they stopped by a university to enroll in a Russian course. "Why do you want to learn Russian? The English that we speak is a very good language," the university secretary asked."Well, we just adopted a Russian baby. When he begins to speak Russian in a few years, we are afraid that we might not be able to understand him," the couple replied.

[wklken]

读入文件，组成一个字符串str
字符串长度：str.length()
String[] arr = str.split(" ")
for循环遍历arr
可以统计非空白字符数及有多少个to

最后toUpperCase()转，输出

[凉岑玉]

[Quote=引用 1 楼 wklken 的回复:]
读入文件，组成一个字符串str
字符串长度：str.length()
String[] arr = str.split(" ")
for循环遍历arr
可以统计非空白字符数及有多少个to

最后toUpperCase()转，输出
[/Quote]
just do it!

[茫茫大海]

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


public class T {
	public static void main(String[] args) throws IOException {
		//读入文件
		FileInputStream fis = new FileInputStream(new File("data.txt"));
		BufferedReader br = new BufferedReader(new InputStreamReader(fis));
		StringBuffer sb = new StringBuffer();
		String str = br.readLine();
		while(str != null) {
			sb.append(str);
			str = br.readLine();
		}
		br.close();
		
		//统计文件的字符数、非空白字符数和单词to的个数
		str = sb.toString();
		int count = str.length();//总共的字符数
		String[] words = str.split(" ");
		int count1 = 0;//非空白字符数
		int count2 = 0;//to的个数
		for(String word : words) {
			count1 += word.length();
			if(word.equals("to")) {
				count2 ++;
			}
		}
		
		System.out.println("文件中总共有" + count + "个字符！");
		System.out.println("文件中总共有" + count1 + "个非空白字符！");
		System.out.println("文件中总共有" + count2 + "个单词to！");
		//文件中的所有大写字母改成小写字母
		str = str.toLowerCase();
		
		//转换后的内容写入文件
		FileOutputStream fos = new FileOutputStream("joke.txt");
		fos.write(str.getBytes());
		fos.close();
	}
}

[ydh85362600]

1.首先算出短文的字符，接住用.trim()得到新的字符串 ~前减后。得到空白
2.1中有了
3.简单的算法
4.。。。。。
不知道行不行呢

[徒步向西的男孩]

3楼正解！