java：Javalin一个简单而现代的Java和Kotlin web框架

# JDK版本1.8
$ java -version
java version "1.8.0_251"
Java(TM) SE Runtime Environment (build 1.8.0_251-b08)
Java HotSpot(TM) 64-Bit Server VM (build 25.251-b08, mixed mode)

$ tree
.
├── pom.xml
└── src
    ├── main
    │   ├── java
    │   │   └── com
    │   │       └── example
    │   │           ├── HelloWorld.java
    │   │           └── User.java
    │   └── resources
    └── test
        └── java

<dependency>
    <groupId>io.javalin</groupId>
    <artifactId>javalin</artifactId>
    <version>4.6.7</version>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <!-- https://mvnrepository.com/artifact/io.javalin/javalin -->
        <dependency>
            <groupId>io.javalin</groupId>
            <artifactId>javalin</artifactId>
            <version>4.6.7</version>
        </dependency>
        <!--log-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.31</version>
        </dependency>
        <!--json-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.3</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
            <version>2.13.3</version>
        </dependency>
    </dependencies>
</project>

package com.example;
import com.fasterxml.jackson.annotation.JsonFormat;
import java.time.LocalDateTime;
public class User {
    private String name;
    private Integer age;
    @JsonFormat(pattern = "yyyy年MM月dd日")
    private LocalDateTime birthday;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public LocalDateTime getBirthday() {
        return birthday;
    }
    public void setBirthday(LocalDateTime birthday) {
        this.birthday = birthday;
    }
}

package com.example;
import io.javalin.Javalin;
import java.time.LocalDateTime;
import java.util.HashMap;
public class HelloWorld {
    public static void main(String[] args) {
        Javalin app = Javalin.create();
        app.get("/", ctx -> {
            User user = new User();
            user.setAge(20);
            user.setName("Tom");
            user.setBirthday(LocalDateTime.now());
            ctx.json(user);
        });
        app.start(7070);
    }
}

{
    "name": "Tom",
    "age": 20,
    "birthday": "2023年03月01日"
}