Java的讀文件和寫文件

1.文件的寫

package cn.edu.hpu.example;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class FileWriterDemo {
	public static void main(String[] args) throws IOException {
		// The name of the file to open.
		String fileName = "temp.txt";

		try {
			// Assume default encoding.
			FileWriter fileWriter = new FileWriter(fileName);

			// Always wrap FileWriter in BufferedWriter.
			BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);

			// Note that write() does not automatically
			// append a newline character.
			bufferedWriter.write("Hello there,");
			bufferedWriter.write(" here is some text.");
			bufferedWriter.newLine();
			bufferedWriter.write("We are writing");
			bufferedWriter.write(" the text to the file.");

			// Always close files.
			bufferedWriter.close();
		} catch (IOException ex) {
			System.out.println("Error writing to file '" + fileName + "'");
			// Or we could just do this:
			// ex.printStackTrace();
		}
	}
}

2.文件的讀

package cn.edu.hpu.example;

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

public class FileDemo {
	public static void main(String[] args) throws IOException {
		// The name of the file to open.
		String fileName = "temp.txt";
		// This will reference one line at a time
		String line = null;
		try {
			// FileReader reads text files in the default encoding.
			FileReader fileReader = new FileReader(fileName);
			// Always wrap FileReader in BufferedReader.
			BufferedReader bufferedReader = new BufferedReader(fileReader);
			while ((line = bufferedReader.readLine()) != null) {
				System.out.println(line);
			}
			// Always close files.
			bufferedReader.close();
		} catch (FileNotFoundException ex) {
			System.out.println("Unable to open file '" + fileName + "'");
		} catch (IOException ex) {
			System.out.println("Error reading file '" + fileName + "'");
			// Or we could just do this:
			// ex.printStackTrace();
		}
	}
}