简介

这是学习JAVA的练习代码, 主要提供工具函数

使用

/*
[
    {id: 1, name: "name1", gender: 1},
    {id: 2, name: "name2", gender: 1},
    {id: 3, name: "name1", gender: 2},
]
*/

/*
[1, 2, 3]
*/
CollectionUtils.pluck(persons, "id", new ArrayList<Integer>())

/*
{1: 1, 2: 1, 3: 2}
*/
CollectionUtils.pluck(persons, "id", "gender", new HashMap<Integer, Ingeger>())

/*
{
    1: [
        {id: 1, name: "name1", gender: 1},
        {id: 2, name: "name2", gender: 1},
    ],
    2: [
        {id: 3, name: "name1", gender: 2},
    ]
}
*/
CollectionUtils.keyBy(persons, "id", Integer.class)

/*
{
    1: [
        {id: 1, name: "name1", gender: 1},
        {id: 2, name: "name2", gender: 1},
    ],
    2: [
        {id: 3, name: "name1", gender: 2},
    ]
}
*/
CollectionUtils.groupBy(persons, "gender", Integer.class)

/*
去重
*/
CollectionUtils.unique(integers, new ArrayList<Integer>())