del util

hutool-core/src/main/java/cn/hutool/core/util/StreamUtil.java

@@ -1,175 +0,0 @@
-package cn.hutool.core.util;
-
-import cn.hutool.core.collection.CollUtil;
-import cn.hutool.core.lang.Assert;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
-import java.util.function.BinaryOperator;
-import java.util.function.Function;
-import java.util.function.Predicate;
-import java.util.stream.Collectors;
-
-/**
- * java Stream工具类
- * <pre>
- *  在实际项目中，我们经常需要处理集合对象, 提取集合元素的某个字段集合。
- *  此工具类可以简化一些代码, 如
- *  原来需要提取User对象的id集合：
- *      1 - 写一个for循环
- *          {@code
- *          List<Long> userIds = new ArrayList<>();
- *          for(User user : userList) {
- *              userIds.add(user.getId());
- *          }
- *          }
- *      2 - 使用java8 引入的stream方式
- *          {@code List<Long> userIds = userList.stream().map(User::getId).collect(Collectors.toList());}
- *
- *      3 - 此工具类提供了更简洁的stream写法(无需每次都写{@code collect(Collectors.toList())})
- *          {@code List<Long> userId = StreamUtil.list(userList, User::getId);}
- * </pre>
- *
- * @author yiming
- */
-public class StreamUtil {
-
-    /**
-     * 将指定List元素的某个field提取成新的List(过滤null元素)
-     *
-     * @param sourceList 原list
-     * @param mapperFunction 映射方法
-     * @return 转化后的list
-     */
-    public static <T, R> List<R> list(List<T> sourceList, Function<T, R> mapperFunction) {
-        if (CollUtil.isEmpty(sourceList)) {
-            return Collections.emptyList();
-        }
-        Assert.notNull(mapperFunction);
-        return sourceList.stream().map(mapperFunction).filter(Objects::nonNull).distinct().collect(Collectors.toList());
-    }
-
-    /**
-     * 获取对象列表的某个字段list
-     *
-     * @param sourceList 源数据
-     * @param mapperFunction 映射方法
-     * @param filter 过滤器
-     * @param <T> 源数据类型
-     * @param <R> 结果数据类型
-     * @return 转化后的列表数据
-     */
-    public static <T, R> List<R> list(List<T> sourceList, Function<T, R> mapperFunction, Predicate<? super T> filter) {
-        if (CollUtil.isEmpty(sourceList)) {
-            return Collections.emptyList();
-        }
-        Assert.notNull(mapperFunction);
-        Assert.notNull(filter);
-        return sourceList.stream().filter(filter).map(mapperFunction).distinct().collect(Collectors.toList());
-    }
-
-    /**
-     * 将指定List元素的某个field提取成新的Set(过滤null元素)
-     *
-     * @param sourceList 原list
-     * @param mapperFunction 映射方法
-     * @return 转化后的set
-     */
-    public static <T, R> Set<R> toSet(List<T> sourceList, Function<T, R> mapperFunction) {
-        return new HashSet<>(list(sourceList, mapperFunction));
-    }
-
-    /**
-     * 将指定List元素的某个field提取成新的Set(过滤null元素)
-     *
-     * @param sourceList 原list
-     * @param mapperFunction 映射方法
-     * @param filter 过滤器
-     * @return 转化后的set
-     */
-    public static <T, R> Set<R> toSet(List<T> sourceList, Function<T, R> mapperFunction, Predicate<T> filter) {
-        return new HashSet<>(list(sourceList, mapperFunction, filter));
-    }
-
-    /**
-     * list 转 map
-     *
-     * @param sourceList 源数据
-     * @param keyMapper key映射
-     * @param valueMapper value映射
-     * @param mergeFunction value合并策略
-     * @param <T> 对象集合类型
-     * @param <K> map键类型
-     * @param <R> map值类型
-     * @return 由list转化而的map
-     */
-    public static <T, K, R> Map<K, R> toMap(List<T> sourceList, Function<T, K> keyMapper, Function<T, R> valueMapper,
-        BinaryOperator<R> mergeFunction) {
-        if (CollUtil.isEmpty(sourceList) || keyMapper == null || valueMapper == null) {
-            return Collections.emptyMap();
-        }
-        return sourceList.stream().collect(Collectors.toMap(keyMapper, valueMapper, mergeFunction));
-    }
-
-    /**
-     * 提取list指定字段转成map
-     *
-     * @param sourceList 原list
-     * @param keyMapper key映射方法
-     * @param valueMapper value映射方法
-     * @return 指定map
-     */
-    public static <T, K, R> Map<K, R> toMap(List<T> sourceList, Function<T, K> keyMapper, Function<T, R> valueMapper) {
-        if (CollUtil.isEmpty(sourceList) || keyMapper == null || valueMapper == null) {
-            return Collections.emptyMap();
-        }
-        return sourceList.stream().collect(Collectors.toMap(keyMapper, valueMapper, (v1, v2) -> v1));
-    }
-
-    /**
-     * 提取list指定字段转成map
-     *
-     * @param sourceList 原list
-     * @param keyMapper key映射方法
-     * @param valueMapper value映射方法
-     * @param filter 过滤器
-     * @return 指定map
-     */
-    public static <T, K, R> Map<K, R> toMap(List<T> sourceList, Function<T, K> keyMapper, Function<T, R> valueMapper,
-        Predicate<? super T> filter) {
-        if (CollUtil.isEmpty(sourceList) || keyMapper == null || valueMapper == null) {
-            return Collections.emptyMap();
-        }
-        return sourceList.stream().filter(filter).collect(Collectors.toMap(keyMapper, valueMapper, (v1, v2) -> v1));
-    }
-
-    /**
-     * list -> map (map值类型同list元素类型)
-     *
-     * @param sourceList 源数据
-     * @param keyMapper key映射
-     * @param <T> 对象集合类型
-     * @param <K> map键类型
-     * @return 由list转化而来的map
-     */
-    public static <T, K> Map<K, T> toMap(List<T> sourceList, Function<T, K> keyMapper) {
-        return toMap(sourceList, keyMapper, Function.identity(), (v1, v2) -> v1);
-    }
-
-    /**
-     * 按指定字段分组
-     *
-     * @param sourceList 原list
-     * @param keyMapper 字段映射
-     * @return 分组
-     */
-    public static <T, K> Map<K, List<T>> groupingBy(List<T> sourceList, Function<T, K> keyMapper) {
-        if (CollUtil.isEmpty(sourceList) || keyMapper == null) {
-            return Collections.emptyMap();
-        }
-        return sourceList.stream().collect(Collectors.groupingBy(keyMapper));
-    }
-}

hutool-core/src/test/java/cn/hutool/core/util/StreamUtilTest.java

@@ -1,179 +0,0 @@
-package cn.hutool.core.util;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.stream.Collectors;
-import org.junit.Assert;
-import org.junit.Test;
-
-/**
- * @author yiming
- * @date 2020/9/4 13:40
- */
-public class StreamUtilTest {
-
-    static List<User> userList = Arrays.asList(
-        new User(1L, "A", 3, true, true, true),
-        new User(2L, "B", 4, true, true, false),
-        new User(3L, "C", 5, true, false, true),
-        new User(4L, "E", 6, true, false, false),
-        new User(5L, "D", 7, false, true, true),
-        new User(6L, "F", 7, false, false, true),
-        new User(7L, "G", 8, false, true, false),
-        new User(8L, "H", 8, false, false, false)
-    );
-
-    @Test
-    public void testList() {
-        List<Long> userIds = StreamUtil.list(userList, User::getId);
-        Assert.assertEquals(userIds.size(), userList.size());
-    }
-
-    @Test
-    public void testListFilter() {
-        // 提取管理员用户名称
-        List<String> names = StreamUtil.list(userList, User::getName, x -> Boolean.TRUE.equals(x.isAdmin));
-        Assert.assertEquals(names.size(), 4);
-    }
-
-    @Test
-    public void testToSet() {
-        Set<Integer> ages = StreamUtil.toSet(userList, User::getAge);
-        Assert.assertEquals(ages.size(), 6);
-    }
-
-    @Test
-    public void testToSetFilter() {
-        // 提取大于6的元素
-        Set<Integer> ages = StreamUtil.toSet(userList, User::getAge, x -> x.getAge() > 6);
-        Assert.assertEquals(ages.size(), 2);
-    }
-
-    @Test
-    public void testToMap() {
-        Map<Long, User> userMap = StreamUtil.toMap(userList, User::getId);
-        Assert.assertEquals(userMap.size(), userList.size());
-    }
-
-    @Test
-    public void testToMapValue() {
-        Map<Long, String> userNameMap = StreamUtil.toMap(userList, User::getId, User::getName);
-        Assert.assertEquals(userNameMap.size(), userList.size());
-    }
-
-    @Test
-    public void testToMapFilter() {
-        // 提取年龄>5的用户姓名map
-        Map<Long, String> userNameMap = StreamUtil.toMap(userList, User::getId, User::getName, x -> x.getAge() > 5);
-        Assert.assertEquals(userNameMap.size(), 5);
-    }
-
-    @Test
-    public void testToMapMerge() {
-        // 提取用户姓名map - 自定义map的value覆盖策略
-        User tempUser1 = new User(10L, "X", 10, true, false, false);
-        User tempUser2 = new User(10L, "Y", 10, true, false, false);
-        List<User> users = new ArrayList<>();
-        users.add(tempUser1);
-        users.add(tempUser2);
-        // 若新的value同原value，取原value
-        Map<Long, String> userNameMap = StreamUtil.toMap(users, User::getId, User::getName, (v1, v2) -> v1);
-        Assert.assertEquals(userNameMap.get(10L), "X");
-        // 若新的value同原value，取新value
-        userNameMap = StreamUtil.toMap(users, User::getId, User::getName, (v1, v2) -> v2);
-        Assert.assertEquals(userNameMap.get(10L), "Y");
-    }
-
-    @Test
-    public void groupingBy() {
-        // 按年龄分组
-        Map<Integer, List<User>> ageGroupMap = StreamUtil.groupingBy(userList, User::getAge);
-        Assert.assertEquals(ageGroupMap.size(), 6);
-    }
-
-    /**
-     * 测试bean
-     */
-    public static class User {
-
-        private Long id;
-        private String name;
-        private int age;
-        private boolean isAdmin;
-        private boolean isSuper;
-        private boolean gender;
-
-        public User() {
-        }
-
-        public User(Long id, String name, int age, boolean isAdmin, boolean isSuper, boolean gender) {
-            this.id = id;
-            this.name = name;
-            this.age = age;
-            this.isAdmin = isAdmin;
-            this.isSuper = isSuper;
-            this.gender = gender;
-        }
-
-        public Long getId() {
-            return id;
-        }
-
-        public void setId(Long id) {
-            this.id = id;
-        }
-
-        public String getName() {
-            return name;
-        }
-
-        public void setName(String name) {
-            this.name = name;
-        }
-
-        public int getAge() {
-            return age;
-        }
-
-        public User setAge(int age) {
-            this.age = age;
-            return this;
-        }
-
-        public String testMethod() {
-            return "test for " + this.name;
-        }
-
-        public boolean isAdmin() {
-            return isAdmin;
-        }
-
-        public void setAdmin(boolean isAdmin) {
-            this.isAdmin = isAdmin;
-        }
-
-        public boolean isIsSuper() {
-            return isSuper;
-        }
-
-        public void setIsSuper(boolean isSuper) {
-            this.isSuper = isSuper;
-        }
-
-        public boolean isGender() {
-            return gender;
-        }
-
-        public void setGender(boolean gender) {
-            this.gender = gender;
-        }
-
-        @Override
-        public String toString() {
-            return "User [name=" + name + ", age=" + age + ", isAdmin=" + isAdmin + ", gender=" + gender + "]";
-        }
-    }
-}