Java的读文件和写文件

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();
}
}
}

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();
}
}
}