更新：
package packet;
import java.util.ArrayList; //java library implementation of List interface
import java.util.Arrays;
import java.util.List; //java library the List interface
import java.util.Random; //for random number generator
import java.io.FileNotFoundException; //for opening a file
import java.io.PrintWriter; //for writing to a file
public class Message
{
private String message;
private int packetLength;
private List<Packet> dividedMessage; //use java library java.util.List
private boolean messageSent;
private Random generator; //use java library java.util.Random
public Message(String theMessage, int thePacketLength)
{
message = theMessage;
packetLength = thePacketLength;
receiveInFile(message);
}
public void send()
{ // divide the message into Packet and store the packets in the list
// dividedMessage
dividedMessage = new ArrayList<Packet>();
List<String> items = Arrays.asList(message.split("\\s*,\\s*"));
int sequenceNumber = packetLength;
String nextPiece = message;
//This is the line of code to create a Packet object using a sequence
//number and a string (represent part of the message)
Packet nextPacket = new Packet(sequenceNumber, nextPiece);
dividedMessage.add(nextPacket);
}
/** Simulates the receipt of the packets of a message. The packets
are not in any particular order and are written to a text file.
@param fileName a string that names the file to be created and the
packets are written to the file.
@return true if the packets are received, or
false if the message was never sent or the file
cannot be created */
public boolean receiveInFile(String fileName)
{
String[] items = message.split(" ");
int numberOfPackets = items.length;
dividedMessage = Arrays.asList(message.split(","));
shuffle(dividedMessage, numberOfPackets);
// container.send();
return messageSent;
}
public String toString()
{
return message;
}
private void shuffle (List<Packet> packetList, int numberOfPackets)
{
if (numberOfPackets > 1)
{
// swap packet at index numberOfPackets - 1 and a random index
Packet temp = packetList.get(numberOfPackets - 1);
int randomIndex = Math.abs(generator.nextInt())
%numberOfPackets;
packetList.set(numberOfPackets - 1, packetList.get(randomIndex));
packetList.set(randomIndex, temp);
shuffle(packetList, numberOfPackets - 1);
} // end if
} // end Shuffle
}// end class Message
原件：
我正在制作一个示例程序，目的是无序地发送数据包并重新排序然后以完整字符串输出数据包。我有订购部分工作正常，所以我没有包括它们，我似乎不知道从这里下一步去哪些，这些类应该采取重新排序的数据包，并使它们成为一个字符串。任何帮助都很棒！
public class Packet implements Comparable<Packet>
{
private int sequence; //sequence number of the packet
private String message; //a part of the message represented by the packet
public Packet(int sequenceNumber, String nextPiece) {
setSequence(sequenceNumber);
setMessage(nextPiece);
Message test = new Message(message, sequence);
}
@Override
public int compareTo(Packet o) {
int comparedSize = o.sequence;
if (this.sequence > comparedSize) {
return 1;
} else if (this.sequence == comparedSize) {
return 0;
} else {
return -1;
}
}
public String toString() {
return message;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getSequence() {
return sequence;
}
public void setSequence(int sequence) {
this.sequence = sequence;
}
//Implement constructor and other methods as necessary
}
import java.util.ArrayList; //java library implementation of List interface
import java.util.List; //java library the List interface
import java.util.Random; //for random number generator
import java.io.FileNotFoundException; //for opening a file
import java.io.PrintWriter; //for writing to a file
public class Message
{
private String message;
private int packetLength;
private List<Packet> dividedMessage; //use java library java.util.List
private boolean messageSent;
private Random generator; //use java library java.util.Random
/**implement constructor */
public Message(String theMessage, int thePacketLength)
{
message = theMessage;
packetLength = thePacketLength;
}
/** Sends this message as a sequence of packets. */
public void send()
{ // divide the message into Packet and store the packets in the list
// dividedMessage
dividedMessage = new ArrayList<Packet>();
int sequenceNumber = 0;
String nextPiece = null;
//This is the line of code to create a Packet object using a sequence
//number and a string (represent part of the message)
Packet nextPacket = new Packet(sequenceNumber, nextPiece);
}
/** Simulates the receipt of the packets of a message. The packets
are not in any particular order and are written to a text file.
@param fileName a string that names the file to be created and the
packets are written to the file.
@return true if the packets are received, or
false if the message was never sent or the file
cannot be created
*/
public boolean receiveInFile(String fileName)
{
// shuffle the packets to simulate their arrival order
int numberOfPackets = 0;
shuffle(dividedMessage, numberOfPackets);
return messageSent;
}
public String toString()
{
return message;
}
private void shuffle (List<Packet> packetList, int numberOfPackets)
{
if (numberOfPackets > 1)
{
// swap packet at index numberOfPackets - 1 and a random index
Packet temp = packetList.get(numberOfPackets - 1);
int randomIndex = Math.abs(generator.nextInt())
%numberOfPackets;
packetList.set(numberOfPackets - 1, packetList.get(randomIndex));
packetList.set(randomIndex, temp);
shuffle(packetList, numberOfPackets - 1);
} // end if
} // end Shuffle
}// end class Message
最初的信息是“在工会的6点见我。”
收到的消息包： 1 Mee 3 e 6 clo 5点' 4吨6 2吨 11离子 7 ck 8英寸 10联合国 9
收到的消息是“在工会6点见我”
答案 0 :(得分：1)
为什么不对ArrayList本身的Packets进行排序，因为您已经实现了Comparable接口？你可以
Collections.sort()。nextPiece附加到字符串。此后你应该有正确的字符串。
答案 1 :(得分：0)
在这里，我可以给你一些提示，但尝试自己编写代码。
首先，使用split(" ")将String 1 Mee 3 e a 6 clo 5 o' 4 t 6 2 t m 11 ion 7 ck 8 in 10 un 9 the拆分为String[]。
假设数字和字符串块交替出现，将它们放入Map<Integer, String>。如果您不想进一步排序，可以使用TreeMap。
最后，遍历Map中的值。将它们添加到StringBuilder，最后使用toString()获取String实例，这应该是结果。
修改：如果Packet implements Comparable<Packet>，TreeSet将为您执行所有排序（因为不会有任何相等的Packet）。请参阅以下代码（为方便起见，将其简化并压缩为单个java文件）。
import java.util.*;
import java.io.FileNotFoundException; //for opening a file
import java.io.PrintWriter; //for writing to a file
public class Message
{
private String message;
private int packetLength;
private List<Packet> dividedMessage; //use java library java.util.List
private boolean messageSent;
private Random generator; //use java library java.util.Random
public Message(String theMessage, int thePacketLength)
{
message = theMessage;
packetLength = thePacketLength;
//receiveInFile(message);
}
public static void main(String[] args)
{
ArrayList<Packet> list = new ArrayList<>();
list.add(new Packet(1, "Mee"));
list.add(new Packet(3, "e a"));
list.add(new Packet(6, "clo"));
list.add(new Packet(5, "o\'"));
list.add(new Packet(4, "t 6 "));
list.add(new Packet(2, "t m"));
list.add(new Packet(11, "ion"));
list.add(new Packet(7, "ck "));
list.add(new Packet(8, "in "));
list.add(new Packet(10, "un"));
list.add(new Packet(9, "the "));
Collections.shuffle(list);
/*
* now shuffled
* read message
*/
TreeSet<Packet> set = new TreeSet<>(list);
StringBuilder builder = new StringBuilder();
for (Packet p: set)
{
builder.append(p.getMessage());
}
System.out.println(builder.toString());
}
public String toString()
{
return message;
}
static class Packet implements Comparable<Packet>
{
private int sequence; //sequence number of the packet
private String message; //a part of the message represented by the packet
public Packet(int sequenceNumber, String nextPiece) {
setSequence(sequenceNumber);
setMessage(nextPiece);
Message test = new Message(message, sequence);
}
@Override
public int compareTo(Packet o) {
int comparedSize = o.sequence;
if (this.sequence > comparedSize) {
return 1;
} else if (this.sequence == comparedSize) {
return 0;
} else {
return -1;
}
}
public String toString() {
return message;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getSequence() {
return sequence;
}
public void setSequence(int sequence) {
this.sequence = sequence;
}
}
}
IMO，Set比List更方便，因为没有相同的元素。如果订单不重要，请使用HashSet;如果订单必须不变，则使用LinkedHashSet;如果需要自然排序，则使用TreeSet。
答案 2 :(得分：0)
我尝试了以下代码，它运行正常：
public static void main(String[] args) {
List<Packet> dividedMessage = new ArrayList<>();
dividedMessage.add(new Packet(1, "Mee"));
dividedMessage.add(new Packet(2, "t m"));
dividedMessage.add(new Packet(3, "e a"));
dividedMessage.add(new Packet(6, "clo"));
dividedMessage.add(new Packet(5, "o'"));
dividedMessage.add(new Packet(4, "t 6 "));
dividedMessage.add(new Packet(11, "ion"));
dividedMessage.add(new Packet(7, "ck"));
dividedMessage.add(new Packet(8, " in"));
dividedMessage.add(new Packet(10, " un"));
dividedMessage.add(new Packet(9, " the"));
Collections.sort(dividedMessage);
String originalMessage = "";
for (Packet packet : dividedMessage)
{
originalMessage += packet.getMessage();
}
System.out.println(originalMessage);
}
我希望这就是你想要的。输出为：Meet me at 6 o'clock in the union
如果你有很多数据包，那么性能可能是一个问题，你可以使用StringBuilder：
StringBuilder sb = new StringBuilder();
for (Packet packet : dividedMessage)
{
sb.append(packet.getMessage());
}