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1.拓展ofEmptyAble函数，简化了判空元素list的操作

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2.ifPresentOrElse现在支持链式调用
3.拓展mapOrElse函数,可用于一些连续的参数校验
4.拓展exec函数，能对NPE和数组越界异常进行友好返回
This commit is contained in:
VampireAchao
2021-11-15 23:09:03 +08:00
committed by achao
parent e021f52563
commit 600f2ff371
2 changed files with 104 additions and 3 deletions
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48
hutool-core/src/test/java/cn/hutool/core/lang/OptTest.java
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@@ -1,5 +1,6 @@
package cn.hutool.core.lang;
import cn.hutool.core.collection.CollectionUtil;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
@@ -9,6 +10,7 @@ import org.junit.Ignore;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.stream.Stream;
@@ -46,11 +48,14 @@ public class OptTest {
@Test
@Ignore
public void ifPresentOrElseTest() {
// 这是jdk9中的新函数，直接照搬了过来
// 存在就打印对应的值，不存在则用{@code System.err.println}打印另一句字符串
Opt.ofNullable("Hello Hutool!").ifPresentOrElse(Console::log, () -> Console.error("Ops!Something is wrong!"));
Opt.empty().ifPresentOrElse(Console::log, () -> Console.error("Ops!Something is wrong!"));
// 拓展为支持链式调用
Opt.empty().ifPresentOrElse(Console::log, () -> Console.error("Ops!Something is wrong!"))
.ifPresentOrElse(Console::log, () -> Console.error("Ops!Something is wrong!"));
}
@Test
@@ -142,6 +147,47 @@ public class OptTest {
Assert.assertNull(user.getNickname());
}
@Test
public void ofEmptyAbleTest() {
// 以前，输入一个CollectionUtil感觉要命，类似前缀的类一大堆，代码补全形同虚设(在项目中起码要输入完CollectionU才能在第一个调出这个函数)
// 关键它还很常用，判空和判空集合真的太常用了...
List<String> past = Opt.ofNullable(Collections.<String>emptyList()).filter(CollectionUtil::isNotEmpty).orElseGet(() -> Collections.singletonList("hutool"));
// 现在，一个ofEmptyAble搞定
List<String> hutool = Opt.ofEmptyAble(Collections.<String>emptyList()).orElseGet(() -> Collections.singletonList("hutool"));
Assert.assertEquals(past, hutool);
Assert.assertEquals(hutool, Collections.singletonList("hutool"));
}
@Test
public void mapOrElseTest() {
// 如果值存在就转换为大写，否则打印一句字符串，支持链式调用、转换为其他类型
String hutool = Opt.ofBlankAble("hutool").mapOrElse(String::toUpperCase, () -> Console.log("yes")).mapOrElse(String::intern, () -> Console.log("Value is not present~")).get();
Assert.assertEquals("HUTOOL", hutool);
}
@Test
public void execTest() {
// 有一些资深的程序员跟我说你这个lambda，双冒号语法糖看不懂...
// 为了尊重资深程序员的意见，并且提升代码可读性，封装了一下 "try catch NPE 和 数组越界"的情况
// 以前这种写法，简洁但可读性稍低，对资深程序员不太友好
List<String> last = null;
String npeSituation = Opt.ofEmptyAble(last).flattedMap(l -> l.stream().findFirst()).orElse("hutool");
String indexOutSituation = Opt.ofEmptyAble(last).map(l -> l.get(0)).orElse("hutool");
// 现在代码整洁度降低，但可读性up，如果再人说看不懂这代码...
String npe = Opt.exec(() -> last.get(0)).orElse("hutool");
String indexOut = Opt.exec(() -> {
List<String> list = new ArrayList<>();
// 你可以在里面写一长串调用链 list.get(0).getUser().getId()
return list.get(0);
}).orElse("hutool");
Assert.assertEquals(npe, npeSituation);
Assert.assertEquals(indexOut, indexOutSituation);
Assert.assertEquals("hutool", npe);
Assert.assertEquals("hutool", indexOut);
}
@Data
@Builder
@NoArgsConstructor