Question

例如我有一个名为file.txt的文件，其中包含个人信息（id，name，salary）：

A123 Anna 3000
A234 Alex 4000
A986 Jame 5000

如何编写允许用户输入人员ID并补充工资的java代码？最终输出如下：

输入ID：A123

输入补充工资：2000

运行程序后

file.txt：

A123 Anna 5000
A234 Alex 4000
A986 Jame 5000

这是我到目前为止所做的，但它没有用：

public static void addDalary() throws IOException {
        String ID, Nanme;
        double salary;


            Scanner console = new Scanner(System.in);
            System.out.print("Enter ID : ");
            String pID = console.nextLine();
            System.out.print("Enter replenish salary: ");
            replenish = console.nextInt();

            Scanner input = new Scanner(new File("file.txt"));
            while (input.hasNext()) {
                ID = input.next();
                Name = input.next();
                salary = input.nextDouble();

                if (ID == pID) {    
                    salary = salary + replenish;
                }
            }
            input.close();
        }

我对这些事情不熟悉。任何帮助都会非常感激。

Answer 1

一种可能的方式可以是这样的

从文件中读取每一行
拆分行
使用更新的数据准备另一行并写入临时文件
最后删除旧文件并将临时文件重命名为旧文件。
现在你完成了。试试上面的算法。

Answer 2

您必须逐行使用从原始文件中读取它的方法。使用新号码搜索并替换薪水。将内容写入新的临时文件。删除原始文件。最后将临时文件替换为原始文件名。以下是执行此操作的代码：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class FileContentUpdater {

    public static void main(String args[]) throws IOException {
        String ID, Name;
        double salary;
        int replenish;

        Scanner console = new Scanner(System.in);
        System.out.print("Enter ID : ");
        String pID = console.nextLine();
        System.out.print("Enter replenish salary: ");
        replenish = console.nextInt();

        File originalFile = new File("file.txt");
        BufferedReader br = new BufferedReader(new FileReader(originalFile));

        // Construct the new file that will later be renamed to the original
        // filename.
        File tempFile = new File("tempfile.txt");
        PrintWriter pw = new PrintWriter(new FileWriter(tempFile));

        String line = null;
        // Read from the original file and write to the new
        // unless content matches data to be removed.
        while ((line = br.readLine()) != null) {

            if (line.contains(pID)) {
                String strCurrentSalary = line.substring(line.lastIndexOf(" "), line.length());
                if (strCurrentSalary != null || !strCurrentSalary.trim().isEmpty()) {
                    int replenishedSalary = Integer.parseInt(strCurrentSalary.trim()) + replenish;
                    System.out.println("replenishedSalary : " + replenishedSalary);
                    line = line.substring(0,line.lastIndexOf(" ")) + replenishedSalary;
                }

            }
            pw.println(line);
            pw.flush();
        }
        pw.close();
        br.close();

        // Delete the original file
        if (!originalFile.delete()) {
            System.out.println("Could not delete file");
            return;
        }

        // Rename the new file to the filename the original file had.
        if (!tempFile.renameTo(originalFile))
            System.out.println("Could not rename file");

    }
}

如何更新.txt文件中的包含java

2 个答案: