如何在 Java 程序中使用外部 jar 依赖？

Question

I'm having trouble figuring out how to use JSoup in my program. I figured you simply needed to have the.jar file in the same project folder but this is not the case. There is very little info on the subject online.

Answer 1

Assuming you have the following directory structure

.
├── Main.java
└── jsoup-1.12.1.jar

and this content in your Main.java

import java.io.IOException;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;

public class Main {

    public static void main(String[] args) throws IOException {
        String url = "http://www.google.com";
        Document doc = Jsoup.connect(url).get();
        String title = doc.title();
        System.out.println(title);
    }

}

In order to be able to compile and run your program, you need to have your jar in your classpath .

Compile your program like this

javac -cp .:jsoup-1.12.1.jar Main.java

And run it like this

java -cp .:jsoup-1.12.1.jar Main

I think this is a good reference point to start learning about Java's classpath

Classpath (Java)