Question

java结果输出至txt

您好，您在http://zhidao.baidu.com/question/228625547.html中的回答对我非常有帮助，现在我想将输出结果保存到txt文件，试了几种方法都有问题，要么是只能输出最后一行，要么是只能输出文件夹下一个txt的统计结果。请帮忙指导一下输出txt的方法，谢谢

Answer 1

帮你修改了一下 你看看可以吗

package com.isoftstone.baidu;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
public class Article {
    //保存文章的内容
    String content;
    //保存分割后的单词集合
    String[] rawWords;
    //保存统计后的单词集合
    String[] words;
    //保存单词对应的词频
    int[] wordFreqs;
    //构造函数，输入文章内容
    //提高部分：从文件中读取
    public Article() {
        content =
                "kolya is one of the richest films i've seen in some time . zdenek sverak plays a confirmed old bachelor ( who's likely to remain so ) , who finds his life as a czech cellist increasingly impacted by the five-year old boy that he's taking care of . though it ends rather abruptly-- and i'm whining , 'cause i wanted to spend more time with these characters-- the acting , writing , and production values are as high as , if not higher than , comparable american dramas . this father-and-son delight-- sverak also wrote the script , while his son , jan , directed-- won a golden globe for best foreign language film and , a couple days after i saw it , walked away an oscar . in czech and russian , with english subtitles . ";
    }
    //对文章根据分隔符进行分词,将结果保存到rawWords数组中
    public void splitWord() {
        //分词的时候，因为标点符号不参与，所以所有的符号全部替换为空格
        final char SPACE = ' ';
        content = content.replace('\'', SPACE).replace(',', SPACE).replace('.', SPACE);
        content = content.replace('(', SPACE).replace(')', SPACE).replace('-', SPACE);
        rawWords = content.split("\\s+");//凡是空格隔开的都算单词，上面替换了', 所以I've 被分成2个 //单词
    }
    //统计词，遍历数组
    public void countWordFreq() {
        //将所有出现的字符串放入唯一的set中，不用map,是因为map寻找效率太低了
        Set<String> set = new TreeSet<String>();
        for (String word : rawWords) {
            set.add(word);
        }
        Iterator ite = set.iterator();
        List<String> wordsList = new ArrayList<String>();
        List<Integer> freqList = new ArrayList<Integer>();
        //多少个字符串未知，所以用list来保存先
        while (ite.hasNext()) {
            String word = (String) ite.next();
            int count = 0;//统计相同字符串的个数
            for (String str : rawWords) {
                if (str.equals(word)) {
                    count++;
                }
            }
            wordsList.add(word);
            freqList.add(count++);
        }
        //存入数组当中
        words = wordsList.toArray(new String[0]);
        wordFreqs = new int[freqList.size()];
        for (int i = 0; i < freqList.size(); i++) {
            wordFreqs[i] = freqList.get(i);
        }
    }
    //根据词频，将词数组和词频数组进行降序排序
    public void sort() {
        class Word {
            private String word;
            private int freq;
            public Word(String word, int freq) {
                this.word = word;
                this.freq = freq;
            }
        }
        //注意：此处排序，1）首先按照词频降序排列， 2）如果词频相同，按照字母降序排列，
        //如 'abc' > 'ab' >'aa'
        class WordComparator implements Comparator {
            public int compare(Object o1, Object o2) {
                Word word1 = (Word) o1;
                Word word2 = (Word) o2;
                if (word1.freq < word2.freq) {
                    return 1;
                } else if (word1.freq > word2.freq) {
                    return -1;
                } else {
                    int len1 = word1.word.trim().length();
                    int len2 = word2.word.trim().length();
                    String min = len1 > len2 ? word2.word : word1.word;
                    String max = len1 > len2 ? word1.word : word2.word;
                    for (int i = 0; i < min.length(); i++) {
                        if (min.charAt(i) < max.charAt(i)) {
                            return 1;
                        }
                    }
                    return 1;
                }
            }
        }
        List wordList = new ArrayList<Word>();
        for (int i = 0; i < words.length; i++) {
            wordList.add(new Word(words[i], wordFreqs[i]));
        }
        Collections.sort(wordList, new WordComparator());
        for (int i = 0; i < wordList.size(); i++) {
            Word wor = (Word) wordList.get(i);
            words[i] = wor.word;
            wordFreqs[i] = wor.freq;
        }
    }
    //将排序结果输出
    public void printResult() {
        System.out.println("Total " + words.length + " different words in the content!");
        for (int i = 0; i < words.length; i++) {
            System.out.println(wordFreqs[i] + "  " + words[i]);
        }
    }
    // 输出到文本
    private void outputResult() {
        File file = new File("C:\\output.txt");
        try {
            if (file.exists()) file.delete();
            BufferedWriter bw = new BufferedWriter(new FileWriter(file));
            StringBuffer out = new StringBuffer();
            for(int i = 0; i < words.length; i++) {
                out.append(wordFreqs[i] + "  " + words[i] + "\n");
            }
            bw.write(out.toString());
            bw.flush();
            bw.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //测试类的功能
    public static void main(String[] args) {
        Article a = new Article();
        a.splitWord();
        a.countWordFreq();
        a.sort();
        a.printResult();
        a.outputResult();
    }
}

追问

您好，您的代码我试了试，能够输出至txt，但是我前边的代码改了，要统计频率的文章是从一个文件夹里读取出来的，现在文件夹里面有多个txt，在println输出到屏幕的情况下能够每个文件分别统计词频，但是到txt后就只有一个txt的统计词频结果了。我感觉是不是第一个txt统计词频之后，把结果写入到了output.txt，第二个txt统计词频之后，又写入了output.txt把原来的结果覆盖掉了？

追答

修改main方法 和 构造方法
content默认为空

//保存文章的内容
String content = "";
public Article(String rootPath) {
try {
File file = new File(rootPath);
String files[] = file.list();
for (int i = 0; i < files.length; i++) {
System.out.println(rootPath + files[i]);
BufferedReader br = new BufferedReader(new FileReader(rootPath + files[i])); //创建读取流
//读取数据
String temp = br.readLine();
String line;
while ((line = br.readLine()) != null) {
temp += line;
}
content += "\n" + temp;
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

public static void main(String[] args) {
Article a = new Article("C:\\temp\\");
a.splitWord();
a.countWordFreq();
a.sort();
a.printResult();
a.outputResult();
}

Answer 2

其实你是已经把所有的内容都输出到哪个txt文件里面了，不过你每次输出的都是输出到了txt的第一行，一行覆盖一行，当然最后只剩下了最后一行，只需要没输出一行之后换行就可以了

Answer 3

使用这个构造方法就可以了，其他代码不要改FileOutputStream(String name,
boolean append)
String name就是txt文件夹的路径 ，后面的参数置为true。这样所有的内容都会保存下了。

你可以看看API中关于这个类的说明！

Answer 4

import java.io.*;
public class Main{
public static void main(String[]args){
PrintWriter out;
try{
out=new PrintWriter("output.txt");//你想要的(路径与)文件名
}catch(FileNotFoundException e){throw new RuntimeException(e);}
/*
…你要输出的东西如out.println("abc");
*/
out.close();
}
}