技术阅读周刊第🔟期

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技术阅读周刊，每周更新。

历史更新

Golang: 14 Shorthand Tricks You Might Not Know! | by Nidhi D | Dec, 2023 | Canopas

URL: https://blog.canopas.com/golang-14-shorthand-tricks-you-might-not-know-8d8d21954c49

同时声明和初始化变量

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// Long form  
var message string  
message = "Hello, Golang!"  
  
// Shorthand  
message := "Hello, Golang!"

声明和初始化多个变量

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// Long form  
var a, b, c int  
a = 1  
b = 2  
c = 3  
  
// Shorthand  
a, b, c := 1, 2, 3

交换变量

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a, b := 1, 2  
  
// Long form  
temp := a  
a = b  
b = temp  
  
// Shorthand  
a, b = b, a

Defer 函数调用

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// Long form  
func cleanup() {  
// Cleanup logic  
}  
defer cleanup()  
  
// Shorthand  
defer func() {  
// Cleanup logic  
}()

检测 Map 中的数据是否存在

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// Long form  
value, exists := myMap[key]  
if !exists {  
    // Key doesn't exist in the map  
}  
  
// Shorthand  
if value, exists := myMap[key]; !exists {  
    // Key doesn't exist in the map  
}

使用下标和值迭代切片

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// Long form  
for i := 0; i < len(numbers); i++ {  
fmt.Println(i, numbers[i])  
}  
  
// Shorthand  
for i, value := range numbers {  
fmt.Println(i, value)  
}

错误检测

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// Long form  
result, err := someFunction()  
if err != nil {  
// Handle the error  
}  
  
// Shorthand  
if result, err := someFunction(); err != nil {  
// Handle the error  
}

创建一个变量的指针

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// Long form  
var x int  
ptr := &x  
  
// Shorthand  
ptr := new(int)

匿名函数

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// Long form  
func add(x, y int) int {  
return x + y  
}  
  
// Shorthand  
add := func(x, y int) int {  
return x + y  
}

创建和初始化 Map

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// Long form  
colors := make(map[string]string)  
colors["red"] = "#ff0000"  
colors["green"] = "#00ff00"  
  
// Shorthand  
colors := map[string]string{  
"red": "#ff0000",  
"green": "#00ff00",  
}

声明多个常量

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// Long form  
const pi float64 = 3.14159  
const maxAttempts int = 3  
  
// Shorthand  
const (  
	pi = 3.14159  
	maxAttempts = 3  
)

Java Mastery Unleashed: 12 Essential Tips Every Developer Must Embrace

URL: https://blog.stackademic.com/boost-your-java-skills-12-must-know-programming-tips-for-java-developers-34f8381ec431

一些常用的 Java 技巧

  • 善用 Lambda 表达式

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    // Before
    List<String> names = new ArrayList<>();  
    for (Person person : people) {  
    names.add(person.getName());  
    }
    // After
    List<String> names = people.stream()  
    .map(Person::getName)  
    .collect(Collectors.toList());

  • 使用 Optionals 替代 null

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    Optional<String> maybeName = Optional.ofNullable(person.getName());  
    String name = maybeName.orElse("Unknown");

  • 使用 stream 简化集合操作

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    List<Integer> evenNumbers = numbers.stream()  
    .filter(num -> num % 2 == 0)  
    .collect(Collectors.toList());

  • String.format 拼接字符串

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    String s1 = "Hello";  
    String s2 = " World";  
    String s = String.format("%s%s", s1, s2);

  • 使用 default method 扩展接口

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    import java.time.LocalDateTime;  
    public interface TimeClient {  
    void setTime(int hour, int minute, int second);  
    void setDate(int day, int month, int year);  
    void setDateAndTime(int day, int month, int year, int hour, int minute, int second);  
    LocalDateTime getLocalDateTime();  
    }

  • 使用枚举替换常量

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    public class Main {
        enum Level { LOW, MEDIUM, HIGH }
        public static void main(String[] args) {
            Level myVar = Level.MEDIUM;
            System.out.println(myVar);
        }
    }

  • 使用 try-with-Resource 管理资源

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    try (FileReader fileReader = new FileReader("example.txt");
         BufferedReader bufferedReader = new BufferedReader(fileReader)) {
        String line = bufferedReader.readLine();
        // Process the file
    } catch (IOException e) {
        // Handle the exception
    }

SpringBoot Webflux vs Vert.x: Performance comparison for hello world case | Tech Tonic

URL: https://medium.com/deno-the-complete-reference/springboot-webflux-vs-vert-x-performance-comparison-for-hello-world-case-41a6bd8e9f8c

本文对比了 SpringBoot Webflux 和 Vert.x 的性能对比

以下是两个框架写的压测接口：

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package hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.web.reactive.config.EnableWebFlux;
import org.reactivestreams.Publisher;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import reactor.core.publisher.Mono;

@SpringBootApplication
@EnableWebFlux
@Controller
public class Application {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class);
    }

    @GetMapping("/")
    @ResponseBody
    public Publisher<String> handler() {
        return Mono.just("Hello world!");
    }
}

// Vert.x
package com.example.starter;  
  
import io.vertx.core.AbstractVerticle;  
import io.vertx.core.Promise;  
import io.vertx.core.http.HttpServer;  
import io.vertx.ext.web.Router;  
  
public class MainVerticle extends AbstractVerticle {  
  
  @Override  
  public void start(Promise<Void> startPromise) throws Exception {  
    HttpServer server = vertx.createHttpServer();  
    Router router = Router.router(vertx);  
  
    router.get("/").respond(ctx -> ctx  
        .response()  
        .putHeader("Content-Type", "text/plain")  
        .end("hello world!"));  
  
    server.requestHandler(router).listen(3000);  
  }  
}

最后直接看对比结果吧：
image.png
image.png
image.png
最终作者根据一个计算公式得出两个框架的得分，规则如下：

  • 差距小于 5% 不得分
  • 5～20 得 1 分
  • 20～50 得两分
  • 大于 50，得三分
    image.png
    最终是 Vert.x 得分超过 Webflux 55%⬆️

不过个人觉得压测结果再好，套上业务后，比如一个接口查询了多个后端服务，后端服务有依赖于多个数据库，最终出来的 RT 大家都差不多。

除非是某些对性能极致要求的场景，比如实时数据分析、物联网中间件等和直接业务不太相关领域。

它的底层依然是 Netty，但比 Netty 提供了跟易用的 API。

Git Cherry Pick Examples to Apply Hot Fixes and Security Patches — Nick Janetakis

URL: https://nickjanetakis.com/blog/git-cherry-pick-examples-to-apply-hot-fixes-and-security-patches?ref=dailydev

讲解了 git cherry-pick 的作用，什么时候该用，什么时候不用。

举个例子：
一些大型的开源项目往往都会有一个主分子，同时维护了不同版本的子分支，有些用户可能就会一直使用一些长期维护的子分支，比如 v2.1.0 \ v2.3.0

但对于大部分的开发者来说主要会维护主分支，也会在主分支上推进一些新功能，这些新功能不一定会同步到上述提到的两个老版本中。

但对于一些安全漏洞，重大 bug 等是需要同步到这些子分支的，但又不能把一些不兼容的新特性同步到子分支中。

此时就可以使用 cherry-pick 这个功能，只将某一个提交给 pick 到目标分支中。

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# Cherry pick more than 1 SHA.
#
# This could be useful if you have a handful of commits that you want to bring over,
# you'll likely want to order them with the oldest commit being first in the list.
git cherry-pick <SHA> <SHA>

# Edit the git commit message for the newly applied commit.
#
# This could be useful if want to customize the git commit message with extra context.
git cherry-pick <SHA> --edit

# Avoid automatically creating the commit which lets you edit the files first.
#
# This could be useful if you need to make manual code adjustments before committing,
# such as applying a security patch which uses an older library with a different API.
git cherry-pick <SHA> --no-commit

文章链接：

#Newletters