【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

交集视图处理

　　　　　　　Set<String>  aSet = new HashSet();
            Set<String> bSet = new HashSet();
            Set<String> cSet = new HashSet();
            Sets.SetView<String> intersection = Sets.intersection(aSet, bSet);
            
            for (String s : intersection) {
                cSet.add(s);
            }
            
            //cSet就是最终交集结果Set

 

 并集/交集/补集/差集/相对差集  的 基本代码

 1 package com.sxd.readLines.aboutDB;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.BufferedWriter;
 5 import java.io.File;
 6 import java.io.FileReader;
 7 import java.io.FileWriter;
 8 import java.io.IOException;
 9 import java.util.HashSet;
10 import java.util.Set;
11 
12 import com.google.common.collect.Sets;
13 
14 public class Test {
15     
16     /**
17      * 
18      * @throws IOException
19      */
20 
21     @org.junit.Test
22     public void test1() throws IOException  {
23         Set<String> set1 = readFile4List(new File("D:/B/1.txt"));
24         Set<String> set2 = readFile4List(new File("D:/B/DB.txt"));
25         
26         Set<String> result1 = Sets.union(set1, set2);//合集，并集
27         Set<String> result2 = Sets.intersection(set1, set2);//交集
28         Set<String> result3 = Sets.difference(set1, set2);//差集 1中有而2中没有的
29         Set<String> 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
30         
31         //可以分别把4种不同结果 写出文件
32         
33         BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(new File("d:/B/result.txt")));
34         bufferedWriter.write("共有:"+result1.size()+"条\r\n");
35         for (String string : result1) {
36             bufferedWriter.write(string+"\r\n");
37         }
38         bufferedWriter.close();
39         
40         
41     }
42     
43     public Set<String> readFile4List(File file) throws IOException{
44         BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
45         Set<String> set = new HashSet<String>();
46         String str = null;
47         while((str =bufferedReader.readLine()) != null){
48             if(str.length() > 6){
49                 set.add(str.substring(3));
50             }else{
51                 set.add(str);
52             }
53             
54         }
55         return set;
56     }
57     
58 
59 }
View Code

 

并集/交集/补集/差集/相对差集  的 静态工具类代码

import com.google.common.collect.Sets;
import org.apache.commons.collections.CollectionUtils;

import java.util.*;
import java.util.stream.Collectors;


/**
 * 集合运算工具集
 *
 * @author xudong.shen
 * @date 2021/12/07
 */
public class CollectionOperationUtil {

    /**
     * 合集，并集
     *
     * @param t t
     * @param list list
     * @return {@link List}<{@link T}>
     */
    public static <T> List<T> union(T t, List<T> list){
        return union(Arrays.asList(t), list);
    }

    /**
     * 交集
     *
     * @param t t
     * @param list list
     * @return {@link List}<{@link T}>
     */
    public static <T> List<T> intersection(T t, List<T> list){
        return intersection(Arrays.asList(t), list);
    }


    /**
     * 差集 1中有而2中没有的
     *
     * @param list list
     * @param t t
     * @return {@link Set}<{@link T}>
     */
    public static <T> List<T> difference(List<T> list, T t){
        return difference(list, Arrays.asList(t));
    }

    /**
     * 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
     *
     * @param list list
     * @param t t
     * @return {@link List}<{@link T}>
     */
    public static <T> List<T> symmetricDifference(List<T> list, T t){
        return symmetricDifference(list, Arrays.asList(t));
    }



    /**
     * 合集，并集
     *
     * @param list1 list1
     * @param list2 list2
     * @return {@link List}<{@link T}>
     */
    public static <T> List<T> union(List<T> list1, List<T> list2){
        if (CollectionUtils.isEmpty(list1) || CollectionUtils.isEmpty(list2)) return Collections.EMPTY_LIST;
        Set<T> union = union(new HashSet<>(list1), new HashSet<>(list2));
        return union.stream().collect(Collectors.toList());
    }

    /**
     * 交集
     *
     * @param list1 list1
     * @param list2 list2
     * @return {@link List}<{@link T}>
     */
    public static <T> List<T> intersection(List<T> list1, List<T> list2){
        if (CollectionUtils.isEmpty(list1) || CollectionUtils.isEmpty(list2)) return Collections.EMPTY_LIST;
        Set<T> intersection = intersection(new HashSet<>(list1), new HashSet<>(list2));
        return intersection.stream().collect(Collectors.toList());
    }


    /**
     * 差集 1中有而2中没有的
     *
     * @param list1 list1
     * @param list2 list2
     * @return {@link Set}<{@link T}>
     */
    public static <T> List<T> difference(List<T> list1, List<T> list2){
        if (CollectionUtils.isEmpty(list1) || CollectionUtils.isEmpty(list2)) return Collections.EMPTY_LIST;
        Set<T> difference = difference(new HashSet<>(list1), new HashSet<>(list2));
        return difference.stream().collect(Collectors.toList());
    }

    /**
     * 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
     *
     * @param list1 list1
     * @param list2 list2
     * @return {@link List}<{@link T}>
     */
    public static <T> List<T> symmetricDifference(List<T> list1, List<T> list2){
        if (CollectionUtils.isEmpty(list1) || CollectionUtils.isEmpty(list2)) return Collections.EMPTY_LIST;
        Set<T> symmetricDifference = symmetricDifference(new HashSet<>(list1), new HashSet<>(list2));
        return symmetricDifference.stream().collect(Collectors.toList());
    }

    /**
     * 合集，并集
     *
     * @param set1 set1
     * @param set2 set2
     * @return {@link Set}<{@link T}>
     */
    public static <T> Set<T> union(Set<T> set1, Set<T> set2){
        if (CollectionUtils.isEmpty(set1) && CollectionUtils.isEmpty(set2)) return Collections.EMPTY_SET;
        if (CollectionUtils.isEmpty(set1)) return set2;
        if (CollectionUtils.isEmpty(set2)) return set1;

        Sets.SetView<T> union = Sets.union(set1, set2);
        Set<T> result = union.stream().collect(Collectors.toSet());
        return result;
    }


    /**
     * 交集
     *
     * @param set1 set1
     * @param set2 set2
     * @return {@link Set}<{@link T}>
     */
    public static <T> Set<T> intersection(Set<T> set1, Set<T> set2){
        if (CollectionUtils.isEmpty(set1) && CollectionUtils.isEmpty(set2)) return Collections.EMPTY_SET;
        if (CollectionUtils.isEmpty(set1) || CollectionUtils.isEmpty(set2)) return Collections.EMPTY_SET;

        Sets.SetView<T> intersection = Sets.intersection(set1, set2);
        Set<T> result = intersection.stream().collect(Collectors.toSet());
        return result;
    }


    /**
     * 差集 1中有而2中没有的
     *
     * @param set1 set1
     * @param set2 set2
     * @return {@link Set}<{@link T}>
     */
    public static <T> Set<T> difference(Set<T> set1, Set<T> set2){
        if (CollectionUtils.isEmpty(set1) && CollectionUtils.isEmpty(set2)) return Collections.EMPTY_SET;
        if (CollectionUtils.isEmpty(set1)) return Collections.EMPTY_SET;


        Sets.SetView<T> difference = Sets.difference(set1, set2);
        Set<T> result = difference.stream().collect(Collectors.toSet());
        return result;
    }


    /**
     * 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
     *
     * @param set1 set1
     * @param set2 set2
     * @return {@link Set}<{@link T}>
     */
    public static <T> Set<T> symmetricDifference(Set<T> set1, Set<T> set2){
        if (CollectionUtils.isEmpty(set1) && CollectionUtils.isEmpty(set2)) return Collections.EMPTY_SET;

        Sets.SetView<T> symmetricDifference = Sets.symmetricDifference(set1, set2);
        Set<T> result = symmetricDifference.stream().collect(Collectors.toSet());
        return result;
    }
}
View Code

 

pom.xml引用

<dependency>
                <groupId>com.google.guava</groupId>
                <artifactId>guava</artifactId>
                <version>18.0</version>
            </dependency>

<dependency>
                <groupId>commons-collections</groupId>
                <artifactId>commons-collections</artifactId>
                <version>3.2.1</version>
            </dependency>

 

posted @ 2017-05-05 15:21  Angel挤一挤  阅读(7890)  评论(0)  编辑  收藏  举报