[java][io][File]文件读写

最新推荐文章于 2024-04-03 15:11:06 发布

原创最新推荐文章于 2024-04-03 15:11:06 发布 · 95 阅读

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本文介绍了一个Java程序，该程序能够实现文件的读取、写入及处理功能。通过自定义类`TextFile`实现了从文件中读取文本、向文件写入文本以及将文本按指定分隔符切分的功能。此外，还演示了如何使用`TreeSet`对读取到的单词进行排序。

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import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.TreeSet;

public class TextFile extends ArrayList<String> {

	private static final long serialVersionUID = 2198370200846025857L;

	/**
	 * 读文件输出为字符串
	 */
	public static String read(String fileName) {
		StringBuffer sb = new StringBuffer();
		try {
			File absoFile = new File(fileName).getAbsoluteFile();
			BufferedReader br = new BufferedReader(new FileReader(absoFile));
			try {
				String s = null;
				while ((s = br.readLine()) != null) {
					sb.append(s).append("\n");
				}
			} finally {
				if (br != null) {
					br.close();
				}
			}
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
		return sb.toString();
	}

	/**
	 * 向文件中写入文本
	 */
	public static void write(String fileName, String text){
		File abFile = new File(fileName).getAbsoluteFile();
		try {
			PrintWriter writer = new PrintWriter(abFile);
			try {
				writer.print(text);
			} finally {
				writer.close();
			}
		} catch (FileNotFoundException e) {
			throw new RuntimeException(e);
		}
	}

	public TextFile(String fileName, String splitter){
		super(Arrays.asList(read(fileName).split(splitter)));
		//split后常留下一个空
		if(get(0).equals(" ")){
			remove(0);
		}
	}

	public TextFile(String fileName){
		this(fileName,"\n");
	}

	public void write(String fileName){
		try {
			PrintWriter out = new PrintWriter(new File(fileName).getAbsoluteFile());
			try {
				for(String item : this){
					out.println(item);
				}
			} finally {
				out.close();
			}
		} catch (FileNotFoundException e) {
			throw new RuntimeException(e);
		}
	}

	public static void main(String[] args) {
		System.out.print(read("d:\\a.txt"));
		write("d:\\a.txt","This is not the end of the file.");
		System.out.print(read("d:\\a.txt"));

		TreeSet<String> words = new TreeSet<String>(new TextFile("d:\\a.txt","\\W+"));
		//打印首字母大写的单词
		System.out.println(words.headSet("a"));
	}

}