diff --git a/hutool-core/src/main/java/cn/hutool/core/util/StreamUtil.java b/hutool-core/src/main/java/cn/hutool/core/util/StreamUtil.java deleted file mode 100644 index c97d2fa64..000000000 --- a/hutool-core/src/main/java/cn/hutool/core/util/StreamUtil.java +++ /dev/null @@ -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 - * 
- *  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 userIds = new ArrayList<>();
- *          for(User user : userList) {
- *              userIds.add(user.getId());
- *          }
- *          }
- *      2 - 使用java8 引入的stream方式
- *          {@code List 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 userId = StreamUtil.list(userList, User::getId);}
- *
- * - * @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 List list(List sourceList, Function 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 源数据类型 - * @param 结果数据类型 - * @return 转化后的列表数据 - */ - public static List list(List sourceList, Function mapperFunction, Predicate 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 Set toSet(List sourceList, Function 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 Set toSet(List sourceList, Function mapperFunction, Predicate 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 对象集合类型 - * @param map键类型 - * @param map值类型 - * @return 由list转化而的map - */ - public static Map toMap(List sourceList, Function keyMapper, Function valueMapper, - BinaryOperator 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 Map toMap(List sourceList, Function keyMapper, Function 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 Map toMap(List sourceList, Function keyMapper, Function valueMapper, - Predicate 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 对象集合类型 - * @param map键类型 - * @return 由list转化而来的map - */ - public static Map toMap(List sourceList, Function 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 Map> groupingBy(List sourceList, Function keyMapper) { - if (CollUtil.isEmpty(sourceList) || keyMapper == null) { - return Collections.emptyMap(); - } - return sourceList.stream().collect(Collectors.groupingBy(keyMapper)); - } -} diff --git a/hutool-core/src/test/java/cn/hutool/core/util/StreamUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/util/StreamUtilTest.java deleted file mode 100644 index c29cded6b..000000000 --- a/hutool-core/src/test/java/cn/hutool/core/util/StreamUtilTest.java +++ /dev/null @@ -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 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 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 names = StreamUtil.list(userList, User::getName, x -> Boolean.TRUE.equals(x.isAdmin)); - Assert.assertEquals(names.size(), 4); - } - - @Test - public void testToSet() { - Set ages = StreamUtil.toSet(userList, User::getAge); - Assert.assertEquals(ages.size(), 6); - } - - @Test - public void testToSetFilter() { - // 提取大于6的元素 - Set ages = StreamUtil.toSet(userList, User::getAge, x -> x.getAge() > 6); - Assert.assertEquals(ages.size(), 2); - } - - @Test - public void testToMap() { - Map userMap = StreamUtil.toMap(userList, User::getId); - Assert.assertEquals(userMap.size(), userList.size()); - } - - @Test - public void testToMapValue() { - Map 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 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 users = new ArrayList<>(); - users.add(tempUser1); - users.add(tempUser2); - // 若新的value同原value，取原value - Map 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> 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 + "]"; - } - } -} \ No newline at end of file