1采用文件保存指定日期的汇率表，提供文件读写操作。2输入日期，姓名，选择源货币和兑换货币，输入金额，计算兑换货币金额。3将每次输入和计算结果记录在银行货币兑换明细表中，采用文件保存该表 Java代码

以下是一个简单的Java代码示例，实现了上述三个功能：

import java.io.*;
import java.util.*;

public class CurrencyExchange {
    private static final String RATE_FILE = "rate_table.txt";
    private static final String LOG_FILE = "exchange_log.txt";
    private static final String[] CURRENCIES = {"USD", "EUR", "JPY", "CNY", "GBP"};
    private static final double[][] RATES = {
        {1.0, 0.82, 110.0, 6.47, 0.72},
        {1.22, 1.0, 133.0, 7.85, 0.87},
        {0.0091, 0.0075, 1.0, 0.059, 0.0065},
        {0.15, 0.12, 16.0, 1.0, 0.11},
        {1.38, 1.15, 154.0, 9.05, 1.0}
    };

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("请输入日期（格式：yyyy-MM-dd）：");
        String date = input.nextLine();
        double[][] rates = loadRates(date);
        if (rates == null) {
            System.out.println("未找到指定日期的汇率表！");
            return;
        }
        System.out.print("请输入姓名：");
        String name = input.nextLine();
        System.out.println("可用货币种类：");
        for (int i = 0; i < CURRENCIES.length; i++) {
            System.out.printf("%d. %s\n", i + 1, CURRENCIES[i]);
        }
        System.out.print("请选择源货币（输入数字）：");
        int srcIndex = input.nextInt() - 1;
        System.out.print("请选择兑换货币（输入数字）：");
        int dstIndex = input.nextInt() - 1;
        System.out.print("请输入金额：");
        double amount = input.nextDouble();
        double srcRate = rates[srcIndex][srcIndex];
        double dstRate = rates[dstIndex][dstIndex];
        double exchangeRate = dstRate / srcRate;
        double result = amount * exchangeRate;
        System.out.printf("%s，您需要兑换 %.2f %s，兑换成 %.2f %s 需要 %.2f %s。\n", 
                          name, amount, CURRENCIES[srcIndex], result, CURRENCIES[dstIndex], exchangeRate, CURRENCIES[dstIndex]);
        logExchange(date, name, CURRENCIES[srcIndex], CURRENCIES[dstIndex], amount, result);
    }

    private static double[][] loadRates(String date) {
        try (Scanner fileScanner = new Scanner(new File(RATE_FILE))) {
            while (fileScanner.hasNextLine()) {
                String line = fileScanner.nextLine();
                String[] parts = line.split(",");
                if (parts[0].equals(date)) {
                    double[][] rates = new double[CURRENCIES.length][CURRENCIES.length];
                    for (int i = 0; i < CURRENCIES.length; i++) {
                        for (int j = 0; j < CURRENCIES.length; j++) {
                            rates[i][j] = Double.parseDouble(parts[i * CURRENCIES.length + j + 1]);
                        }
                    }
                    return rates;
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

    private static void logExchange(String date, String name, String srcCurrency, String dstCurrency, double srcAmount, double dstAmount) {
        try (PrintWriter out = new PrintWriter(new FileWriter(LOG_FILE, true))) {
            out.printf("%s,%s,%s,%s,%.2f,%.2f\n", date, name, srcCurrency, dstCurrency, srcAmount, dstAmount);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

其中，`loadRates`方法从文件中加载指定日期的汇率表；`logExchange`方法记录每次兑换的明细；`main`方法则实现了输入、计算和输出功能。该示例仅作为参考，实际应用中可能需要进行更多的错误处理和优化。