filerw.java

一个模拟银行间存款

package Bank;
import java.util.*;
import java.io.*;

/**
 * 对保存帐户信息的数据文件进行读取操作
 * 文件格式：同类数据在同一行保存，多个数据以分隔符分开
 * @author rainliu
 */
public class FileRW extends ADataFile implements IDataFile {

	/** 保存帐号信息的数据文件 */
	private static String dataFileName = "src/banking/account.dat";

	public FileRW() {
	}

	/**
	 * 从数据文件中读取帐户信息
	 * @return List      帐户信息的参数名和参数值
	 */
	public List readAccountInfo() {
		//保存一组用户信息的列表
		List accountList = new ArrayList();
		//检查数据文件是否存在
		if (checkFile(dataFileName)==false) return null;
		
		try
		{
			java.io.FileReader r = new FileReader(dataFileName);
			BufferedReader br = new BufferedReader(r);
			//读取帐号ID
			String accountId = br.readLine();
			if (accountId==null) return null;
			//password
			String password = br.readLine();
			if (password==null) return null;
			//金额
			String strBalance = br.readLine();
			if (strBalance==null) return null;
			//分出各个帐户的信息
			StringTokenizer stId = new StringTokenizer(accountId,",");
			StringTokenizer stPass = new StringTokenizer(password,",");
			StringTokenizer stBalance = new StringTokenizer(strBalance,",");
			while (stId.hasMoreTokens()) {
				String tempID = stId.nextToken();
				String tempPass = stPass.nextToken();
				String tempBalance = stBalance.nextToken();
				double tempB = Double.parseDouble(tempBalance);
				AccountInfo ai = new AccountInfo(tempID,tempPass,tempB);
				accountList.add(ai);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return accountList;
	}

	/**
	 * 将帐户信息列表写入数据文件中
	 * @param  List      要保存到文件中的帐户信息
	 * @return boolean   操作成功返回true，否则返回false
	 */
	public boolean writeAccountInfo(List accountList) {
		boolean result = false;
		//检查数据文件是否存在
		if (!checkFile(dataFileName)) return false;

		try
		{
			//将帐户信息写入文件中
			java.io.FileWriter w = new FileWriter(dataFileName);
			BufferedWriter bw = new BufferedWriter(w);
			//所有帐户名字信息以“，”连接
			String allId = "";
			String allPass = "";
			String allBalance = "";
			for (int i=0;i<accountList.size();i++) {
				AccountInfo tempAccount = (AccountInfo)accountList.get(i);
				allId += tempAccount.accountId + ",";
				allPass += tempAccount.password + ",";
				allBalance += tempAccount.balance + ",";
			}
			String ls = System.getProperty("line.separator");
			bw.write(allId+"\n");
			bw.write(allPass+"\n");
			bw.write(allBalance+"\n");
			bw.flush();
			bw.close();
			result = true;
		} catch (Exception e) {
			e.printStackTrace();
		}
		return result;
	}

	/**
	 * 检查文件是否存在，若不存在，则新建
	 * @return boolean   操作成功返回true，否则返回false
	 */
	public boolean checkFile(String fileName) {
		boolean result = false;
		try {
			//如果该文件不存在，则在banking目录下创建一个新的文件
			File file = new File(fileName);
			if (!file.exists()) {
				//若路径不存在，先创建路径
				//File pathFile = dataFile.getParentFile();
				File pathFile = new File(file.getParent());
				if (!pathFile.exists()) {
					pathFile.mkdirs();
				}
				//在指定路径下创建该文件
				file.createNewFile();
			}
			result = true;
		} catch (IOException e) {
			e.printStackTrace();
		}
		return result;
	}

}