集合中数据以名称为依据转换成Map

问题描述：

现在存在一个集合，集合中存在重复数据，需要以名称唯一，其余数据也进行批量保存，但是其余数据保存的时候，不能对重复数据进行保存，也就是说集合中存在名称唯一，但其余数据存在相同或者不相同的，针对这种情况进行保存？

解决思路：

将上述的集合转换成map,通过key value形式进行保存，这样的话名称就保持唯一了，但是此时的value存在重复数据甚至属性为空的情况，再通过遍历将属性为空进行去掉，对于数据中存在重复数据的话，就通过数据层进行判断，如果存在相同的数据就保存，存在不相同的数据就不进行保存。

简单代码演示：

演示jdk8的新特性将集合转换成map

package com.orange.test;

import com.orange.student.Student;
import org.apache.commons.lang3.StringUtils;
import org.springframework.util.CollectionUtils;

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

public class IterateHashMapExample {
    public static void main(String[] args) {
        List<Student> list = new ArrayList<>();
        Student s = new Student("李四",18,"2022-02-16 12:00:35","");
        Student s1 = new Student("张飞",19,"2022-02-18 12:00:35","2");
        Student s2 = new Student("张飞",19,"2022-02-18 12:00:35","3");// --
        Student s3 = new Student("张飞",19,"2022-02-18 12:00:35","");// --
        Student s4 = new Student("张飞",19,"2022-02-18 12:00:35","");// --
        Student s5 = new Student("张飞",19,"2022-02-18 12:00:35","6");// --
        Student s6 = new Student("王五",19,"","7");
        Student s7 = new Student("王五",19,"2022-02-18 12:00:35","8");
        Student s8 = new Student("王五",19,"2022-02-18 12:00:35","");
        list.add(s);
        list.add(s1);
        list.add(s2);
        list.add(s3);
        list.add(s6);
        list.add(s4);
        list.add(s5);
        list.add(s8);
        list.add(s7);
        Map<String, List<Student>> coursesMap = list.stream().collect(Collectors.groupingBy(Student::getName));
        System.out.println(coursesMap.keySet().size());
        
        
        for (Map.Entry<String, List<Student>> stringListEntry : coursesMap.entrySet()) {
            System.out.println(stringListEntry.getKey());
            System.out.println(stringListEntry.getValue());
        }
    }

package com.orange.student;


public class Student {
    private String name;
    private int age;
    private String sendTime;
    private String completeTime;

    public Student() {
    }

    public Student(String name, int age, String sendTime, String completeTime) {
        this.name = name;
        this.age = age;
        this.sendTime = sendTime;
        this.completeTime = completeTime;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSendTime() {
        return sendTime;
    }

    public void setSendTime(String sendTime) {
        this.sendTime = sendTime;
    }

    public String getCompleteTime() {
        return completeTime;
    }

    public void setCompleteTime(String completeTime) {
        this.completeTime = completeTime;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", sendTime='" + sendTime + '\'' +
                ", completeTime='" + completeTime + '\'' +
                '}';
    }
}

数据库批量插入时排除属性重复数据

问题描述：

近期在对数据进行批量插入时，发现如果数据中存在相同的属性时，此时不应该插入相关的数据，而是在数据库中对重复的数据不进行批量插入，从而达到数据的唯一性。

解决思路：

在插入数据时进行判断，如果存在相同的数据，则不进行插入，如果不存在相同的数据，则进行插入

slq案例：

方式一：

INSERT INTO personOffice(personID, officeID) 
SELECT '2', (SELECT officeID FROM offices WHERE title = 'Berlin') FROM dual
WHERE NOT EXISTS (SELECT * FROM personOffice WHERE personId = 2 AND officeID = 1)

方式二：

INSERT INTO personOffice (personID, officeID) 
VALUES ('2', (SELECT officeID FROM offices WHERE title = 'Berlin')) 
WHERE NOT EXISTS (SELECT * FROM personOffice WHERE personID = 2 AND officeID = 1)