[Spring Boot] 2. Reflection_3.Ex03

Annotation / @RequestMapping

package ex03;
//A회사

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME) // 언제 작동할지 정함 runtime or source(comfile시)
@Target(ElementType.METHOD)
public @interface RequestMapping {
    String value();
}

Dispatcher

package ex03;

import java.lang.reflect.Method;
import java.lang.reflect.Parameter;

public class Dispatcher {
    UserController con;

    public Dispatcher(UserController con) {
        this.con = con;
    }

    public void routing(String path) { // /login
        Method[] methods = con.getClass().getMethods();

        for (Method method : methods) {
            RequestMapping rm = method.getAnnotation(RequestMapping.class);

            if (rm == null) continue; // 다음 for문으로 바로 넘어감

            // /login?username=ssar
            // RequestMapping("/login")
            if (path.startsWith(rm.value())) {
                try {
                    // 1. 파라미터 검사
                    Parameter[] parameters = method.getParameters();
                    if (parameters.length > 0 && parameters[0].getType().equals(String.class)) {
                        String username = path.split("\\?")[1].split("=")[1];
                        method.invoke(con, username);
                    } else {
                        method.invoke(con);
                    }


                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }

UserController

package ex03;

public class UserController {
    // /login?username=ssar&password=1234
    @RequestMapping("/login")
    public void login(String username) {
        System.out.println("login call: " + username);
    }

    @RequestMapping("/join")
    public void join() {
        System.out.println("join call");
    }

    @RequestMapping("/logout")
    public void logout() {
        System.out.println("logout call");
    }

    @RequestMapping("/userinfo")
    public void userinfo() {
        System.out.println("userinfo call");
    }
}

App

package ex03;

public class App {
    public static void main(String[] args) {
        Dispatcher ds = new Dispatcher(new UserController());
        // 파라미터가 있으면 넣고 없으면 안 넣고
        ds.routing("/login?username=ssar");
    }
}

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=54732:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\spring_lec\ref\out\production\ref ex03.App
login call: ssar

Process finished with exit code 0

package ex03;

public class App {
    public static void main(String[] args) {
        Dispatcher ds = new Dispatcher(new UserController());
        // 파라미터가 있으면 넣고 없으면 안 넣고
        ds.routing("/login?username=ssar");
        ds.routing("/join");
    }
}

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=54748:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\spring_lec\ref\out\production\ref ex03.App
login call: ssar
join call

Process finished with exit code 0