java if(response.equals("验证成功,完成登录")) { System.out.println(response); response="";//登录成功后向用户发送 new Thread(new ReadThread(in)).start(); sendStr = sc.next(); String a; while (sendStr != null) { out.println(sendStr); System.out.println(sendStr); a=sendStr; try {/// fileWriter.write("ip地址："); fileWriter.write(ipAddress); fileWriter.write(" "); fileWriter.write("时间："); fileWriter.write(" "); fileWriter.write(" "); fileWriter.write(a); fileWriter.close(); }catch (IOException e) {} sendStr = sc.next(); System.out.println(sendStr); } }改进这段代码让它可以多次向配置文件中输入字符串

可以将文件写入的操作封装成一个方法，每次发送消息时调用该方法写入配置文件。同时，需要将文件写入的操作放在一个 try-catch 块中，避免发生异常导致程序崩溃。

改进后的代码如下：

if(response.equals("验证成功,完成登录")) {
    System.out.println(response);
    response="";//登录成功后向用户发送
    new Thread(new ReadThread(in)).start();
    sendStr = sc.next();
    while (sendStr != null) {
        out.println(sendStr);
        System.out.println(sendStr);
        try {
            writeToFile(ipAddress, sendStr);
        } catch (IOException e) {
            e.printStackTrace();
        }
        sendStr = sc.next();
        System.out.println(sendStr);
    }
}

// 写入文件的方法
private void writeToFile(String ipAddress, String message) throws IOException {
    FileWriter fileWriter = new FileWriter("config.txt", true);
    fileWriter.write("ip地址：" + ipAddress + " ");
    fileWriter.write("时间：" + new Date() + " ");
    fileWriter.write(message);
    fileWriter.close();
}