package action;

import java.io.BufferedWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Properties;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;

public class TestVelocity extends HttpServlet {

	private static final long serialVersionUID = 1L;

	@Override
	public void init() throws ServletException {
		super.init();
	}

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// 载入配置文件
		Properties properties = new Properties();
		properties.setProperty("file.resource.loader.class", "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
		Velocity.init(properties);

		// 取得VelocityContext作用域
		VelocityContext context = new VelocityContext();
		// 将list放入context作用域
		context.put("list", getNames());
		// 将city放入context作用域
		context.put("city", "ShangHai");

		Template template = null;
		String templateFile = "example.vm";

		try {
			// 载入模板文件
			template = Velocity.getTemplate(templateFile, "UTF-8");
		} catch (ResourceNotFoundException rnfe) {
			System.out.println("Example : error : cannot find template " + templateFile);
		} catch (ParseErrorException pee) {
			System.out.println("Example : Syntax error in template " + templateFile + ":" + pee);
		}
		
		BufferedWriter writer = new BufferedWriter(response.getWriter());

		if (template != null)
			template.merge(context, writer);
		writer.flush();
		writer.close();
	}

	private ArrayList<String> getNames() {
		ArrayList<String> list = new ArrayList<>();

		list.add("Oracle");
		list.add("MySQL");
		list.add("SQLServer");

		return list;
	}
}