英文:
Is there a way to make a string from ArrayList elements?
问题
我想要求用户输入一条消息：
> "按以下格式输入消息："TO FROM MESSAGE : KEY""
用户输入示例：
> 1 2 嗨，你好吗？: bubble123
然后，我想让SecureMessage类返回这条消息。然而，我不知道如何创建消息部分的字符串，因为getMessage()方法需要一个分配给它的字符串。
SecureMessage类不应该有任何修改器。SecureMessage中的所有字段都从Message类中设置。
public class SecureMessage {private String message;private String sourceName;private String destName;private String key;public SecureMessage(String message, String sourceName, String destName, String key){this.message = message;this.sourceName = sourceName;this.destName = destName;this.key = key;}public String getMessage(String key){return message + " 来自SecureMessage类";}public String getSourceName(){return sourceName + " 来自SecureMessage类";}public String getDestName(){return destName + " 来自SecureMessage类";}}
import java.util.ArrayList;import java.util.Scanner;public class Message {public static void main(String[] args) {Scanner keyboard = new Scanner(System.in);String message = "空白", sourceName = "空白", destName = "空白", key = "空白", messageInput, userMessageDetails;ArrayList<String> messageInputList = new ArrayList<>();System.out.println("按照格式 TO FROM MESSAGE : KEY 输入消息\n示例 --- 1 2 嗨，你好吗？: bubble123");userMessageDetails = keyboard.nextLine();String str = userMessageDetails;String[] tokens = str.split(" ");for(String s : tokens){messageInputList.add(s);}System.out.println(messageInputList);System.out.println("");int x = messageInputList.size();destName = messageInputList.get(0);sourceName = messageInputList.get(1);key = messageInputList.get(x-1);//--这是我迷失的地方，因为我需要向SecureMessage的getMessage()方法传递一个字符串---// message = ???;// 我找到了如何打印这些项，但这不是一个字符串...// for(int i = 2; i <= (x-3); i++){// System.out.print(messageInputList.get(i) + " ");// }//------------------------------------------------------------------------------------------------------SecureMessage secMsg = new SecureMessage(message, sourceName, destName, key);System.out.println(secMsg.getDestName());System.out.println(secMsg.getSourceName());System.out.println(secMsg.getMessage(key));}}
英文:
I want to ask the user for a message:
> "Enter a message in the following format: "TO FROM MESSAGE : KEY"
Example input from user:
> 1 2 hey there how are you : bubble123
Then, I want to have the SecureMessage class return the message. However, I do not know how to create a String of the message part, as the getMessage() message requires a String assigned to it.
The SecureMessage class should not have any mutators in it. All fields in SecureMessage are set from the Message class.
public class SecureMessage {private String message;private String sourceName;private String destName;private String key;public SecureMessage(String message, String sourceName, String destName, String key){this.message = message;this.sourceName = sourceName;this.destName = destName;this.key = key;}public String getMessage(String key){return message + " from SecureMessage class";}public String getSourceName(){return sourceName + " from SecureMessage class";}public String getDestName(){return destName + " from SecureMessage class";}}
import java.util.ArrayList;import java.util.Scanner;public class Message {public static void main(String[] args) {Scanner keyboard = new Scanner(System.in);String message = "blank", sourceName = "blank", destName = "blank", key = "blank", messageInput, userMessageDetails;ArrayList<String> messageInputList = new ArrayList<>();System.out.println("Enter message in form TO FROM MESSAGE : KEY \nExample --- 1 2 hey there how are you? : bubble123");userMessageDetails = keyboard.nextLine();String str = userMessageDetails;String[] tokens = str.split(" ");for(String s : tokens){messageInputList.add(s);}System.out.println(messageInputList);System.out.println("");int x = messageInputList.size();destName = messageInputList.get(0);sourceName = messageInputList.get(1);key = messageInputList.get(x-1);//--this is where I am lost, because I need to pass a string to the SecureMessage getMessage() method---// message = ???;// I found out how to print the items, however this is not a string...// for(int i = 2; i <= (x-3); i++){// System.out.print(messageInputList.get(i) + " ");// }//------------------------------------------------------------------------------------------------------SecureMessage secMsg = new SecureMessage(message, sourceName, destName, key);System.out.println(secMsg.getDestName());System.out.println(secMsg.getSourceName());System.out.println(secMsg.getMessage(key));}}
答案1
得分: 2
这应该可以：
message = String.join(" ", messageInputList.subList(2, x-2));
英文:
This should do it:
message = String.join(" ", messageInputList.subList(2, x-2));
答案2
得分: 1
根据我所看到的，由于你是通过" "进行分割，那么你的消息将在messageInputList.get(2)和messageInputList.get(x-3)之间进行分割。简单的方法是使用循环并连接字符串。类似于：
String s_message = ""for(int i = 2; i <= (x-3); i++){s_message = s_message + messageInputList.get(i) + " "}
英文:
So for what I see, as you split by " ", then you will have your message split between messageInputList.get(2) and messageInputList.get(x-3).
The easy way is having a for and concatenate strings. Something like:
String s_message = "";for(int i = 2; i <= (x-3); i++){s_message = s_message + messageInputList.get(i) + " ";}
答案3
得分: 1
这将收集从索引2到x-2的messageInputList中的元素，并将它们收集到一个名为message的字符串中，您可以将其传递给您的SecureMessage类。
英文:
message = IntStream.range(2, x - 2).mapToObj(messageInputList::get).collect(Collectors.joining(" "));
This will collect the elements from your messageInputList from index 2 to x-2 and collect them to a singular String message which you can pass to your SecureMessage class.
答案4
得分: 0
我认为可以更简单一些：
public static void main(String[] args) {Scanner scan = new Scanner(System.in);System.out.println("输入消息数据：");System.out.println("-------------------");System.out.print("目标名称：");String destName = scan.next();System.out.print("源名称：");String sourceName = scan.next();System.out.print("密钥：");String key = scan.next();System.out.println("消息（多行，双击回车结束）：");scan.useDelimiter("\n\n\n");String message = scan.next().trim();SecureMessage secMsg = new SecureMessage(message, sourceName, destName, key);System.out.println(secMsg.getDestName());System.out.println(secMsg.getSourceName());System.out.println(secMsg.getMessage(key));}
英文:
I think it could be much more simplier:
public static void main(String[] args) {Scanner scan = new Scanner(System.in);System.out.println("Enter message data.");System.out.println("-------------------");System.out.print("Destination name: ");String destName = scan.next();System.out.print("Source name: ");String sourceName = scan.next();System.out.print("Key: ");String key = scan.next();System.out.println("Message (multi-line, double ENTER to finish):");scan.useDelimiter("\n\n\n");String message = scan.next().trim();SecureMessage secMsg = new SecureMessage(message, sourceName, destName, key);System.out.println(secMsg.getDestName());System.out.println(secMsg.getSourceName());System.out.println(secMsg.getMessage(key));}
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