HuTool工具类

Author: enjoyCoding666

pom.xml

@@ -15,6 +15,12 @@
   </properties>
 
   <dependencies>
+    <dependency>
+      <groupId>cn.hutool</groupId>
+      <artifactId>hutool-all</artifactId>
+      <version>5.8.6</version>
+    </dependency>
+
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>

src/main/java/com/hutool/CollUtilsDemo.java

@@ -0,0 +1,46 @@
+package com.hutool;
+
+import cn.hutool.core.collection.CollUtil;
+import cn.hutool.core.util.StrUtil;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class CollUtilsDemo {
+
+    public static void main(String[] args) {
+        new CollUtilsDemo().pageDemo();
+    }
+
+    /**
+     * pageNo   页码，从0开始计数，0表示第一页
+     * pageSize 每页的条目数
+     *
+     */
+    public void pageDemo() {
+        List<String> list = Arrays.asList("1","2","3","4");
+        List<String> pageList = CollUtil.page(0, 2, list);
+        pageList.forEach(System.out::println);
+    }
+
+    public void findOneDemo() {
+        List<String> list = Arrays.asList("2","3");
+        String str = CollUtil.findOne(list, num -> StrUtil.equals("2", num));
+        System.out.println(str);
+    }
+
+    public void getDemo() {
+        List<String> list = Arrays.asList("1","2","3","4");
+        String str = CollUtil.get(list, 0);
+        System.out.println(str);
+    }
+
+    public void addAllDemo() {
+        List<String> list = Arrays.asList("1","2","3","4");
+        List<String> list2 = null;
+        //自带null的判断，不需要再重复判断
+        CollUtil.addAll(list, list2);
+        list.forEach(System.out::println);
+    }
+
+}

src/main/java/com/hutool/ConvertDemo.java

@@ -0,0 +1,33 @@
+package com.hutool;
+
+import cn.hutool.core.convert.Convert;
+import com.alibaba.fastjson.JSON;
+
+import java.util.List;
+
+public class ConvertDemo {
+
+    public static void main(String[] args) {
+        new ConvertDemo().convertToListDemo();
+    }
+
+    /**
+     *  转换为指定类型数组
+     */
+    public void convertArrayDemo() {
+        String[] b = { "1", "2", "3", "4" };
+        Integer[] intArray = Convert.toIntArray(b);
+        System.out.println(JSON.toJSONString(intArray));
+    }
+
+
+    /**
+     * 转换为list
+     */
+    public void convertToListDemo() {
+        String[] strArr = {"a", "b", "c", "d"};
+        List<String> strList = Convert.toList(String.class, strArr);
+        System.out.println(strList);
+    }
+
+}

src/main/java/com/hutool/DateUtilDemo.java

@@ -0,0 +1,44 @@
+package com.hutool;
+
+import cn.hutool.core.date.DateField;
+import cn.hutool.core.date.DateTime;
+import cn.hutool.core.date.DateUtil;
+
+import java.util.Date;
+
+public class DateUtilDemo {
+
+    public static void main(String[] args) {
+        new DateUtilDemo().format();
+    }
+
+    /**
+     * 字符串转日期
+     */
+    public void parse() {
+        String dateStr = "2017-03-01";
+        Date date = DateUtil.parse(dateStr);
+        System.out.println(date);
+    }
+
+    /**
+     * 字符串转日期。按格式
+     */
+    public void parsePattern() {
+        String dateStr = "2017-03-01 01:21:32";
+        Date date = DateUtil.parse(dateStr, "yyyy-MM-dd hh:mm:ss");
+        System.out.println(date);
+    }
+
+    /**
+     * 日期转字符串。按格式
+     */
+    public void format() {
+        Date date = new Date();
+        String dateStr = DateUtil.format(date, "yyyy-MM-dd hh:mm:ss");
+        System.out.println(dateStr);
+    }
+
+
+
+}

src/main/java/com/hutool/IdUtilsDemo.java

@@ -0,0 +1,63 @@
+package com.hutool;
+
+import cn.hutool.core.lang.Snowflake;
+import cn.hutool.core.util.IdUtil;
+
+public class IdUtilsDemo {
+
+
+    public static void main(String[] args) {
+        new IdUtilsDemo().snowFlake();
+    }
+
+    /**
+     * 获取随机UUID
+     */
+    public void uuidDemo() {
+        String uuid = IdUtil.randomUUID();
+        //格式：cbb021c7-cb48-44cd-b8ba-814620ee4340
+        System.out.println(uuid);
+    }
+
+    /**
+     * 简化的UUID，去掉了横线
+     */
+    public void simpleUUIDDemo() {
+        String uuid = IdUtil.simpleUUID();
+        //格式：a7e0edfb17ac4120a03842f938f88d34
+        System.out.println(uuid);
+    }
+
+    /**
+     * 雪花算法。获取唯一id。
+     */
+    public void getNextIdDemo() {
+        long id = IdUtil.getSnowflakeNextId();
+        //格式：1648328806748430336
+        System.out.println(id);
+
+        String idStr = IdUtil.getSnowflakeNextIdStr();
+        //格式："1648328806752624640"
+        System.out.println(idStr);
+    }
+
+
+    /**
+     * 雪花算法。配合终端ID和数据中心ID。
+     */
+    public void snowFlake() {
+        //workerId     终端ID
+        // datacenterId 数据中心ID
+        Snowflake snowflake = IdUtil.getSnowflake(1, 1);
+        long id = snowflake.nextId();
+        //格式：1648328965712121856
+        System.out.println(id);
+
+        String idStr = snowflake.nextIdStr();
+        //格式：1648328965716316160
+        System.out.println(idStr);
+
+    }
+
+
+}

src/main/java/com/hutool/ListUtilsDemo.java

@@ -0,0 +1,16 @@
+package com.hutool;
+
+import cn.hutool.core.collection.CollUtil;
+import cn.hutool.core.collection.ListUtil;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class ListUtilsDemo {
+
+    public void page() {
+        List<String> list = Arrays.asList("1","2","3","4");
+        List<String> pageList = ListUtil.page(0, 2, list);
+        pageList.forEach(System.out::println);
+    }
+}

src/main/java/com/hutool/StrUtilsDemo.java

@@ -0,0 +1,16 @@
+package com.hutool;
+
+import cn.hutool.core.util.StrUtil;
+
+public class StrUtilsDemo {
+
+    public void equalDemo() {
+        String num = "2";
+        if (StrUtil.equals("2", num)) {
+            System.out.println(num);
+        }
+    }
+
+
+
+}