add.java

上次小组练习做的一个学生信息管理小系统 控制台的

package system;

import java.io.*;

public class Add {
	public void addData(String str) throws IOException {
		String s1 = "", s2 = "", s3 = "";
		File file = new File("d:\\data.txt");
		if (file.exists())// 如果文件data.txt存在
		{
			try {
				BufferedReader in = new BufferedReader(new FileReader(
						"d:\\data.txt"));

				while ((s1 = in.readLine()) != null)

					s2 += s1 + "\n";// 把文件中的每行数据全部放进一个字符串s2
				s2 += str + "\n"; // 再把s2与形参str相连接放进s2
				BufferedReader in2 = new BufferedReader(new StringReader(s2));
				PrintWriter out = new PrintWriter(new BufferedWriter(
						new FileWriter("d:\\data.txt")));

				while ((s3 = in2.readLine()) != null) {
					out.println(s3);
				}
				out.close();

			} catch (IOException e) {
			}
		} else {
			System.err.println("File data.txt Missing!");
		}
	}
}