例如，我有一个名为 file.txt 的文件，其中包含个人信息(身份证、姓名、薪水):
A123 Anna 3000
A234 Alex 4000
A986 Jame 5000
如何编写允许用户输入个人 ID 并补充工资的 Java 代码？
最终输出将如下所示:
输入ID:A123
输入补薪:2000
运行程序后的文件.txt:
A123 Anna 5000
A234 Alex 4000
A986 Jame 5000
这是我到目前为止所做的，但没有奏效:
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();
}
我对这些东西很陌生。任何帮助将不胜感激。
你必须使用逐行从原始文件中读取它的方法。搜索薪水并将其替换为新数字。将内容写入新的临时文件。删除原文件。最后将临时文件替换为原来的文件名。这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");
}
}