让我们假设您想要将列表分割为多个块的类作为库类。

所以让我们说这个类被称为“shared”，in应该是final，以确保它不会被扩展。

   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.List;

public final class Shared {
List<Integer> input;
int portion;

public Shared(int portion, Integer... input) {
    this.setPortion(portion);
    this.setInput(input);
}

public List<List<Integer>> listToChunks() {
    List<List<Integer>> result = new ArrayList<List<Integer>>();
    int size = this.size();
    int startAt = 0;
    int endAt = this.portion;

    while (endAt <= size) {

        result.add(this.input.subList(startAt, endAt));
        startAt = endAt;
        endAt = (size - endAt < this.portion && size - endAt > 0) ? (this.size()) : (endAt + this.portion);
    }

    return result;
}

public int size() {
    return this.input.size();
}

public void setInput(Integer... input) {
    if (input != null && input.length > 0)
        this.input = Arrays.asList(input);
    else
        System.out.println("Error 001 : please enter a valid array of integers.");
}

public void setPortion(int portion) {
    if (portion > 0)
        this.portion = portion;
    else
        System.out.println("Error 002 : please enter a valid positive number.");
}
}

接下来，让我们尝试从另一个持有公共静态void main(String…args)

public class exercise {

public static void main(String[] args) {
    Integer[] numbers = {1, 2, 3, 4, 5, 6, 7};
    int portion = 2;
    Shared share = new Shared(portion, numbers);
    System.out.println(share.listToChunks());   
}
}

现在，如果输入一个整数数组[1,2,3,4,5,6,7]，分区为2。 结果将是[[1,2]，[3,4]，[5,6]，[7]]

只是要明确一点，这还需要更多的测试…

public class Splitter {

public static <T> List<List<T>> splitList(List<T> listTobeSplit, int size) {
    List<List<T>> sublists= new LinkedList<>();
    if(listTobeSplit.size()>size) {
    int counter=0;
    boolean lastListadded=false;

    List<T> subList=new LinkedList<>();

    for(T t: listTobeSplit) {           
         if (counter==0) {               
             subList =new LinkedList<>();
             subList.add(t);
             counter++;
             lastListadded=false;
         }
         else if(counter>0 && counter<size-1) {
             subList.add(t);
             counter++;
         }
         else {
             lastListadded=true;
             subList.add(t);
             sublists.add(subList);
             counter=0;
         }              
    }
    if(lastListadded==false)
        sublists.add(subList);      
    }
    else {
        sublists.add(listTobeSplit);
    }
    log.debug("sublists: "+sublists);
    return sublists;
 }
}

Apache Commons Collections 4在ListUtils类中有一个分区方法。下面是它的工作原理:

import org.apache.commons.collections4.ListUtils;
...

int targetSize = 100;
List<Integer> largeList = ...
List<List<Integer>> output = ListUtils.partition(largeList, targetSize);

你也可以使用FunctionalJava库- List有分区方法。这个库有自己的集合类型，你可以将它们来回转换为java集合。

import fj.data.List;

java.util.List<String> javaList = Arrays.asList("a", "b", "c", "d" );

List<String> fList = Java.<String>Collection_List().f(javaList);

List<List<String> partitions = fList.partition(2);

这里讨论了一个类似的问题，Java:将List拆分为两个子列表?

主要可以使用子列表。更多细节:subblist

返回该列表中frommindex(包含)和toIndex(不包含)之间部分的视图。(如果fromIndex和toIndex相等，返回的列表为空。)返回的列表受此列表支持，因此返回列表中的更改将反映在此列表中，反之亦然。返回的列表支持该列表支持的所有可选列表操作…

Java8流，一个表达式，没有其他库:

List<String> input = ...
int partitionSize = ...

 Collection<List<String>> partitionedList = IntStream.range(0, input.size())
    .boxed()
        .collect(Collectors.groupingBy(partition -> (partition / partitionSize), Collectors.mapping(elementIndex -> input.get(elementIndex), Collectors.toList())))
            .values();

测试:

List<String> input = Arrays.asList("a", "b", "c", "d", "e", "f", "g", "h" ,"i");

partitionSize = 1 - > [[a], [b], [c], [d], [e], [f], [g], [h],[我]] partitionSize = 2 - > [[a, b], c, d, e, f, g, h,[我]] partitionSize = 3 - > [a, b, c, d, e, f, g, h,我]] partitionSize = 7 - > [[a, b, c, d, e, f, g], [h,我]] partitionSize = 100 -> [[a, b, c, d, e, f, g, h, i]]