如何进行集合切批

当拿到的集合数量很大，需要分组

第一种集合切批

 <!--Lists.partition要用的依赖-->
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>21.0</version>
        </dependency>

　　

package com.java.test.collectdemo;

import com.google.common.collect.Lists;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @Description:
 * @Author: Yourheart
 * @Create: 2022/11/10 17:50
 */
@Slf4j
public class CollectDemo {

    @Test
    public void googleSplitCollect(){
        List<String> listStr=new ArrayList<>();
        for (int i=0;i<10;i++){
            Date date = new Date();
            SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
            String format = simpleDateFormat.format(date);
            listStr.add(format+" "+i);
        }
        List<List<String>> lists = Lists.partition(listStr, 4);
        lists.forEach(a->{
            log.info(a.toString());
        });
    }
}

　　

 

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.java</groupId>
    <artifactId>test-study</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/>
    </parent>

    <dependencies>
        <!--tomcat容器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--lombok依赖-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
        </dependency>
        <!--引入junit单元测试依赖-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--判断空的用法  -->
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.oracle.database.jdbc/ojdbc8 -->
        <dependency>
            <groupId>com.oracle.database.jdbc</groupId>
            <artifactId>ojdbc8</artifactId>
            <version>12.2.0.1</version>
        </dependency>
        <!--springboot整合mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <!--添加fastjson依赖-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.70</version>
        </dependency>
        <!-- 热部署模块 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional> <!-- 这个需要为 true 热部署才有效 -->
        </dependency>
        <!--ThreadFactoryBuilder的依赖包,多线程使用-->
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>30.1-jre</version>
        </dependency>

<!--        <dependency>-->
<!--            <groupId>com.google.code.google-collections</groupId>-->
<!--            <artifactId>google-collect</artifactId>-->
<!--            <version>snapshot-20080530</version>-->
<!--        </dependency>-->
        <!--Lists.partition要用的依赖-->
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>21.0</version>
        </dependency>


    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
        <finalName>study</finalName>
    </build>


</project>

　　第二种集合切批

   <!--ListUtils.partition使用的依赖-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-collections4</artifactId>
            <version>4.4</version>
        </dependency>

　　

 @Test
    public void apacheSplitCollect(){
        List<String> listStr=new ArrayList<>();
        for (int i=0;i<10;i++){
            Date date = new Date();
            SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
            String format = simpleDateFormat.format(date);
            listStr.add(format+" "+i);
        }
        List<List<String>> partition = ListUtils.partition(listStr, 4);
        partition.forEach(b->{
            log.info(b.toString());
        });
    }