(Remove text) Write a program that removes all the occurrences of a specified string from a text file. For example, invoking java Exercise12_11 John filename removes the string John from the specified file. Your program should get the arguments from the command line.并且创建文本文件

以下是一个Java程序示例，可以从文本文件中删除指定字符串：

import java.io.*;

public class RemoveStringFromFile {
    public static void main(String[] args) {
        if (args.length != 2) {
            System.out.println("Usage: java RemoveStringFromFile string filename");
            System.exit(1);
        }

        String stringToRemove = args[0];
        String filename = args[1];

        // 读取文件内容
        StringBuilder sb = new StringBuilder();
        try (BufferedReader reader = new BufferedReader(new FileReader(filename))) {
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line).append(System.lineSeparator());
            }
        } catch (IOException e) {
            System.out.println("Error reading file: " + filename);
            System.exit(1);
        }

        // 删除指定字符串
        String content = sb.toString().replaceAll(stringToRemove, "");

        // 写入文件
        try (BufferedWriter writer = new BufferedWriter(new FileWriter(filename))) {
            writer.write(content);
        } catch (IOException e) {
            System.out.println("Error writing file: " + filename);
            System.exit(1);
        }

        System.out.println("String " + stringToRemove + " removed from file " + filename);
    }
}

该程序从命令行获取要删除的字符串和文件名，读取指定文件的内容，删除所有出现的指定字符串，然后将修改后的内容写回到原始文件中。使用System.lineSeparator()可以跨平台地获取换行符。可以使用以下命令来编译和运行该程序：

javac RemoveStringFromFile.java
java RemoveStringFromFile John file.txt

该程序会从file.txt文件中删除所有出现的字符串"John"。如果文件不存在或无法读取/写入，程序将终止并输出错误消息。