Server.java

package application;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

public class Server {
		
	//DICT为词典，MAX_LENGTH为词典中的最大词长		
	private static final HashSet<String> DICT = new HashSet<>();  		
	//private static final List<String> DIC = new ArrayList<>(); HashSet的contains方法查找速度比ArrayList更快		
	private static int MAX_LENGTH; 					
	
	//加载词典
	static{  
		String line = null;
        try {  
        	int max = 1;
        	BufferedReader reader = new BufferedReader(new FileReader("/Users/lidawei/Downloads/dic.txt"));
        	while((line = reader.readLine()) != null){
	        	DICT.add(line);  	     	      
	            if(line.length()>max){  
	                max=line.length();  
	            }  
        	}	             
            MAX_LENGTH = max;   
        } catch (IOException ex) {  
            System.err.println("词典装载失败:"+ex.getMessage());  
        }       
    }
	
	//正向最大匹配算法（MM算法），最长词优先匹配
	public static List<String> maximumMatching(String text){		
		//result存储分词后的结果
		List<String> result = new ArrayList<>();
		while(text.length() > 0){		
	        int len = MAX_LENGTH; 	        
	        //如果待切分字符串的长度小于词典中的最大词长，则令最大词长等于待切分字符串的长度
	        if(text.length() < len){
	            len = text.length();  
	        } 	        
	        //取指定的最大长度的文本去词典里面匹配  
	        String tryWord = text.substring(0, 0+len); 
	        while(!DICT.contains(tryWord)){  	        	
	        	//如果长度已经减为一且在词典中仍未找到匹配，则按长度为一切分  
	            if(tryWord.length() == 1){  
	                break;  
	            }         	
	        	//如果匹配不到，则长度减一继续匹配  
	            tryWord = tryWord.substring(0, tryWord.length()-1);               	            
	        }
	        result.add(tryWord);        
	        //从待切分字符串中去除已经分词完的部分
	        text = text.substring(tryWord.length());  
	    }  
	    return result;  	      
	}
	
	
	public Server(){
		
		try {
			ServerSocket serverSocket = new ServerSocket(8899);
		    Socket socket = serverSocket.accept();

		    InputStreamReader isr = new InputStreamReader(socket.getInputStream());
		    BufferedReader in = new BufferedReader(isr);
		    String receive = in.readLine();
		    System.out.println("服务器收到的词为：" + receive);
		    
		    //计算结果      	
	    	List<String> list = maximumMatching(receive);
			String string = "";
			for(String s : list){
				string += s + " ";
			}			
		    
		    PrintWriter out = new PrintWriter(socket.getOutputStream(),true);
			out.println(string);
			
			serverSocket.close();
			
		} catch (IOException e) {
			// TODO 自动生成的 catch 块
			e.printStackTrace();
		}		  
	}
	
	public static void main(String[] args){
		Server server = new Server();
	}

}