I want to create a Servlet war file with OpenJDK on CentOS7. Without mvn. With no internet connection.

It takes about 5 minutes. Other than installing unzip, non-root users can also go. The degree of pollution of the environment should be minimal.

** (Target environment) ** CentOS 7 1810 (equivalent to RHEL 7.6) Minimal Install No internet connection

** (Implemented on a terminal connected to the Internet) **

1. 1. Download OpenJDK 13 and transfer it to the CentOS server. https://jdk.java.net/13/ (Linux/x64) openjdk-13_linux-x64_bin.tar.gz 187MB. About 1 minute to download.

2. Download unzip and transfer it to your CentOS server.

• If you can use "yum install unzip" on the CentOS server, that's it. http://mirror.centos.org/centos/7/os/x86_64/Packages/unzip-6.0-20.el7.x86_64.rpm 169KB. Download a few seconds.

3. 3. Download Open Liberty and transfer it to your CentOS server. https://openliberty.io/downloads/#runtime_releases （All GA Features）openliberty-19.0.0.9.zip 141MB. About 2 minutes to download.

** (Implemented on CentOS server) **

1. 1. Deploy OpenJDK.

# tar xf openjdk-13_linux-x64_bin.tar.gz

 → You can create a directory called jdk-13.

 2. unzip install.

#### **`# sudo rpm -i unzip-6.0-20.el7.x86_64.rpm`**

3. 3. Expand Open Liberty.

# unzip openliberty-19.0.0.9.zip

 → You can create a directory called wlp.

 4. Create a directory for the sample app.
```# mkdir -p sample/src```
```# mkdir -p sample/webcontent/web-inf/classes```
```# mkdir -p sample/webcontent/web-inf/lib```

 5. Create Servlet source.

cat << 'EOF' > sample/src/Hello.java

import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;

@WebServlet("/") public class Hello extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out = response.getWriter(); out.println("Hello!"); } } EOF

 6. Servlet, compile.

#### **`# jdk-13/bin/javac sample/src/Hello.java \`**
```java \

```  -d sample/webcontent/web-inf/classes \```
```  -cp "wlp/dev/api/spec/*"```
 → sample / WebContent / WEB-INF / classes / Hello.class file, you can

 7. Create a war file.

#### **`# jdk-13/bin/jar cf sample/sample.war -C sample/WebContent .`**

→ sample / sample.war file can be created.

** (Operation check) **

1. 1. Open Liberty, move. # export java_home=~/jdk-13 # wlp/bin/server start → If the CentOS server port 9080 is used by another service, edit the wlp / usr / servers / defaultServer / server.xml file and change the httpPort from 9080 to another appropriate number.

2. put the war file.

# cp sample/sample.war wlp/usr/servers/defaultServer/dropins/

 → ```A CWWKT0016I: Web application available (default_host): http: // localhost: 9080 / sample / `` `appears in wlp / usr / servers / defaultServer / logs / messages.log.

 3. 3. curl, connect.

#### **`# curl http://localhost:9080/sample/`**

"Hello!" Comes out.

4. (Optional) Open Liberty, stop. wlp/bin/server stop