添加split工具类

chenweijie · chenweijie · commit eab2471ef6b1 · 2019-05-28T23:48:27.000+08:00
diff --git a/src/main/java/com/chen/algorithm/SplitList.java b/src/main/java/com/chen/algorithm/SplitList.java
@@ -0,0 +1,78 @@
+package com.chen.algorithm;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-05-08 16:54
+ */
+public class SplitList {
+
+
+    public static <T> List<List<T>> partList(List<T> source, int n) {
+
+        if (source == null) {
+            return null;
+        }
+
+        if (n == 0) {
+            return null;
+        }
+        List<List<T>> result = new ArrayList<List<T>>();
+        // 集合长度
+        int size = source.size();
+        // 余数
+        int remaider = size % n;
+        System.out.println("余数:" + remaider);
+        // 商
+        int number = size / n;
+        System.out.println("商:" + number);
+
+        for (int i = 0; i < number; i++) {
+            List<T> value = source.subList(i * n, (i + 1) * n);
+            result.add(value);
+        }
+
+        if (remaider > 0) {
+            List<T> subList = source.subList(size - remaider, size);
+            result.add(subList);
+        }
+        return result;
+
+
+    }
+
+    /**
+     * 将待邀请的成员列表分成n个组
+     *
+     * @param source
+     * @param n
+     * @return
+     */
+    private <T>List<List<T>> splitList(List<T> source, int n) {
+
+
+        List<List<T>> result = new ArrayList<>();
+        //(先计算出余数)
+        int remaider = source.size() % n;
+        //然后是商
+        int number = source.size() / n;
+        //偏移量
+        int offset = 0;
+        for (int i = 0; i < n; i++) {
+            List<T> value;
+            if (remaider > 0) {
+                value = source.subList(i * number + offset, (i + 1) * number + offset + 1);
+                remaider--;
+                offset++;
+            } else {
+                value = source.subList(i * number + offset, (i + 1) * number + offset);
+            }
+            result.add(value);
+        }
+        return result;
+
+    }
+
+}
diff --git a/src/main/java/com/chen/api/util/DateUtils.java b/src/main/java/com/chen/api/util/DateUtils.java
@@ -0,0 +1,89 @@
+package com.chen.api.util;
+
+import java.sql.Timestamp;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import java.util.Date;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-05-16 14:46
+ */
+public class DateUtils {
+
+
+    public static void main(String[] args) throws ParseException {
+
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
+
+
+        //    1.Calendar 转化 String
+
+        Calendar calendat = Calendar.getInstance();
+
+
+        String dateStr = sdf.format(calendat.getTime());
+
+
+//        2.String 转化Calendar
+
+        String str = "2012-5-27";
+        Date date = null;
+        try {
+            date = sdf.parse(str);
+        } catch (ParseException e) {
+            e.printStackTrace();
+        }
+
+        Calendar calendar = Calendar.getInstance();
+
+        calendar.setTime(date);
+
+
+//        3.Date 转化String
+
+
+        dateStr = sdf.format(new Date());
+
+
+//        4.String 转化Date
+
+        str = "2012-5-27";
+
+
+        date = sdf.parse(str);
+
+
+//        5.Date 转化Calendar
+
+        calendar = Calendar.getInstance();
+
+        calendar.setTime(new java.util.Date());
+
+
+//        6.Calendar转化Date
+
+        calendar = Calendar.getInstance();
+
+        date = calendar.getTime();
+
+
+//        7.String 转成 Timestamp
+
+        Timestamp ts = Timestamp.valueOf("2012-1-14 08:11:00");
+
+
+//        8.Date 转 TimeStamp
+
+        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+
+        String time = df.format(new Date());
+
+        ts = Timestamp.valueOf(time);
+
+
+    }
+
+
+}
diff --git a/src/main/test/com/chen/test/TestCompare.java b/src/main/test/com/chen/test/TestCompare.java
@@ -0,0 +1,47 @@
+package com.chen.test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-05-14 21:35
+ */
+public class TestCompare {
+
+
+    public static void main(String[] args) {
+
+
+        List<Integer> listA =new ArrayList<>();
+        listA.add(1);
+        listA.add(2);
+        listA.add(3);
+
+
+        List<Integer> listB =new ArrayList<>();
+        listA.add(6);
+        listA.add(5);
+        listA.add(4);
+
+
+        listA.addAll(listB);
+
+
+//        for (int i = 0; i < listA.size(); i++) {
+//            System.out.println(listA.get(i));
+//        }
+
+
+
+        double shouldNum = (double) 10 / 3;
+        System.out.println(shouldNum);
+        int num = (int) Math.ceil(shouldNum);
+        System.out.println(num);
+
+
+
+
+    }
+
+}
diff --git a/src/main/test/com/chen/test/TestList.java b/src/main/test/com/chen/test/TestList.java
@@ -0,0 +1,30 @@
+package com.chen.test;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-05-16 18:14
+ */
+public class TestList {
+
+
+    public static void main(String[] args) {
+
+
+        Set<Integer> set = new HashSet<>();
+
+
+        List<Integer> list = new ArrayList<>(null);
+
+        for (Integer a : list) {
+            System.out.println(a);
+        }
+
+    }
+
+
+}
diff --git a/src/main/test/com/chen/test/TestSubList.java b/src/main/test/com/chen/test/TestSubList.java
@@ -0,0 +1,30 @@
+package com.chen.test;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-05-08 18:45
+ */
+public class TestSubList {
+
+    public static void main(String[] args) {
+
+
+        Integer[] integers = {1, 2, 3, 4, 5, 6};
+
+        List<Integer> integerList = Arrays.asList(integers);
+
+        List<Integer> integers1 = integerList.subList(3, 4);
+
+
+        System.out.println(integers1);
+
+
+
+    }
+
+
+
+}
