【Sets】使用Google Guava工程中Sets工具包，实现集合的并集/交集/补集/差集

获取两个txt文档的内容~存储进集合中求集合的并集/交集/补集/差集

package com.sxd.readLines.aboutDB;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;

import com.google.common.collect.Sets;

public class Test {
    
    /**
     * 
     * @throws IOException
     */

    @org.junit.Test
    public void test1() throws IOException  {
        Set set1 = readFile4List(new File("D:/B/1.txt"));
        Set set2 = readFile4List(new File("D:/B/DB.txt"));
        
        Set result1 = Sets.union(set1, set2);//合集，并集
        Set result2 = Sets.intersection(set1, set2);//交集
        Set result3 = Sets.difference(set1, set2);//差集 1中有而2中没有的
        Set result4 = Sets.symmetricDifference(set1, set2);//相对差集 1中有2中没有  2中有1中没有的 取出来做结果
        
        //可以分别把4种不同结果 写出文件
        
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(new File("d:/B/result.txt")));
        bufferedWriter.write("共有:"+result1.size()+"条\r\n");
        for (String string : result1) {
            bufferedWriter.write(string+"\r\n");
        }
        bufferedWriter.close();
        
        
    }
    
    public Set readFile4List(File file) throws IOException{
        BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
        Set set = new HashSet();
        String str = null;
        while((str =bufferedReader.readLine()) != null){
            if(str.length() > 6){
                set.add(str.substring(3));
            }else{
                set.add(str);
            }
            
        }
        return set;
    }
    

}