導航

• 引言
• 一、Lists.partition

引言

本文用于記錄工作中常用到的 Guava 工具類的使用。
依賴引入：

<dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>20.0</version></dependency>

一、Lists.partition

該方法用于分割大List，對于一些需要批量入參的接口，為了避免一次請求的數據量過大，通?？梢圆捎梅峙埱蟮姆绞?。

例如，設想這樣的場景，我需要根據供應商id列表查詢存儲在另一個系統的供應商列表信息。但是我有1萬條供應商id，甚至更多，為了避免單次請求超時或者接口負載過重，可以分批請求，負載到不同的機器上。

方法簽名與返回值

public static List<List> partition(List list, int size)

用法樣例

public static void main(String[] args) {List<Integer> numList = new ArrayList<>();// 1~1000for (int i = 1; i <= 1000; i++) {numList.add(i);}System.out.println("分組前List=" + numList);Integer size = 100;List<List<Integer>> partitions = Lists.partition(numList, size);System.out.println("分組后的List=" + partitions); }

輸出結果（部分）：

分組前List=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, …]
分組后的List=[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100], [101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170,…],[…],[…]]

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