Java读取txt文件内容并求交集并集差集对称差集合去重

Java读取两个txt内容并作集合运算

文件内容及格式

完整代码

package com.example.fortotest;


import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.nio.file.Files;
import java.util.HashSet;
import java.util.Objects;

public class Day3 {

    public static final String SPLIT_SYMBOL = ",";

    public static void main(String[] args) {
        try {
            // 将st1记为集合A str2文件记为集合B

            // 逗号连接的数字字符串
            String file1 = "E:\\str1.txt";
            File filePath1 = new File(file1);

            HashSet<Long> hashSet1 = new HashSet<>();
            BufferedReader bufferedReader1 = new BufferedReader(new InputStreamReader(Files.newInputStream(filePath1.toPath())));
            String str1;
            while ((str1 = bufferedReader1.readLine()) != null) {
                String[] split = str1.split(SPLIT_SYMBOL);
                for (String s : split) {
                    hashSet1.add(Long.parseLong(s.trim()));
                }
            }


            // 以行划分的数字字符串
            String file2 = "E:\\str2.txt";
            File filePath2 = new File(file2);

            // 交集
            HashSet<Long> intersection = new HashSet<>();

            // 并集
            HashSet<Long> unionSet = new HashSet<>(hashSet1);

            // str2与str1的差集
            HashSet<Long> str2AndStr1DifferenceSet = new HashSet<>();


            String str2;
            BufferedReader bufferedReader2 = new BufferedReader(new InputStreamReader(Files.newInputStream(filePath2.toPath())));
            while (!Objects.equals(str2 = bufferedReader2.readLine(), "") && str2 != null) {

                long l = Long.parseLong(str2.trim());
                if (hashSet1.contains(l)) {

                    // 交集
                    intersection.add(l);

                } else {

                    // 并集
                    unionSet.add(l);

                    // A对B的差集
                    str2AndStr1DifferenceSet.add(l);
                }
            }


            // 对称差集
            HashSet<Long> symmetricDifferenceSet = new HashSet<>(unionSet);
            symmetricDifferenceSet.removeAll(intersection);


            // str2对str1的差集
            HashSet<Long> str1AndStr2DifferenceSet = new HashSet<>(symmetricDifferenceSet);
            str1AndStr2DifferenceSet.removeAll(str2AndStr1DifferenceSet);


            System.out.printf("A∩B(交集) : %s%n", intersection);
            System.out.printf("A∪B(并集) : %s%n", unionSet);
            System.out.printf("A−B(str1与str2的差集) : %s%n", str1AndStr2DifferenceSet);
            System.out.printf("B-A(str2与str1的差集) : %s%n", str2AndStr1DifferenceSet);
            System.out.printf("A⊕B(对称差集) : %s%n", symmetricDifferenceSet);

            HashSet<Long> a = new HashSet<>(intersection);
            HashSet<Long> b = new HashSet<>(intersection);
            a.addAll(str1AndStr2DifferenceSet);
            b.addAll(str2AndStr1DifferenceSet);

            System.out.printf("集合A去重后 : %s%n", a);
            System.out.printf("集合B去重后 : %s%n", b);


        } catch (Exception e) {
            throw new RuntimeException(e);
        }


    }
}

执行结果