我们经常会用程序提供对外的http服务,如 REST 风格的 API 提供给其他的客户来调用我们的服务或者进行一些信息的查询。我们会将这些程序写成WEB程序,提供这样的REST服务。我这里介绍用jetty(一个高性能的Servlet服务器,纯Java编写)编写一个嵌入式的HttpServer。例子的内容很简单,只是提供一些提示。
代码如下:
package test; import org.eclipse.jetty.server.Request; import org.eclipse.jetty.server.Server; import org.eclipse.jetty.server.handler.AbstractHandler; import org.eclipse.jetty.server.handler.ContextHandler; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * <pre> * JettyExampleServer.java * @author kanpiaoxue<br> * @version 1.0 * Create Time 2014年8月28日 下午4:05:25<br> * Description : 利用Jetty实现简单的嵌入式Httpserver * </pre> */ public class JettyExampleServer { private static final Logger LOGGER = LoggerFactory .getLogger(JettyExampleServer.class); /** * <pre> * @param args * </pre> */ public static void main(String[] args) { try { // 进行服务器配置 Server server = new Server(8080); LOGGER.info("server start."); ContextHandler context = new ContextHandler(); // 设置搜索的URL地址 context.setContextPath("/search"); context.setResourceBase("."); context.setClassLoader(Thread.currentThread() .getContextClassLoader()); server.setHandler(context); context.setHandler(new HelloHandler()); // 启动服务器 server.start(); server.join(); } catch (Exception e) { e.printStackTrace(); } } } class HelloHandler extends AbstractHandler { private static final Logger LOGGER = LoggerFactory .getLogger(JettyExampleServer.class); @Override public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { /** * <pre> * 从 URL 里面得到传递过来的参数: * http://localhost:8080/search?query=hello * 如果你需要传递更多的参数,可以这么写: * http://localhost:8080/search?query=hello&name=ZhangLili * 从这里开始,你可以写自己的代码逻辑。 * * [注意:GET方法的请求,URL 的最大长度是 1024个字节] * </pre> */ String query = request.getParameter("query"); // String name = request.getParameter("name"); LOGGER.info(String.format("receive query: %s", query)); String result = "welcome to my server."; if (null != query && query.equals("hello")) { result = query + ", " + result; } LOGGER.info(String.format("response is: %s", result)); // 将服务器处理后的结果返回给调用URL的客户端 print(baseRequest, response, result); } /** * <pre> * @param baseRequest * @param response * @param result 需要返回给客户的结果 * @throws IOException * 将结果 result 返回给客户 * </pre> */ private void print(Request baseRequest, HttpServletResponse response, String result) throws IOException { response.setContentType("text/json;charset=utf-8"); response.setStatus(HttpServletResponse.SC_OK); baseRequest.setHandled(true); response.getWriter().println(result); } }
它需要的jar请看附件。附件中有完整的代码,下载之后将lib目录的jar都放在classpath下面,该程序就可以运行。访问地址,如:http://localhost:8080/search?query=hello
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下面的例子是用jetty嵌入式server实现HttpServlet的例子。可以进行GET和POST请求
package test; import org.eclipse.jetty.server.Server; import org.eclipse.jetty.servlet.ServletContextHandler; import org.eclipse.jetty.servlet.ServletHolder; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import test.servlet.SearchServlet; /** * <pre> * JettyServletExampleServer.java * @author kanpiaoxue<br> * @version 1.0 * Create Time 2014年9月2日 下午4:53:49<br> * Description : 利用Jetty实现简单的嵌入式Httpserver,利用HttpServlet进行编程 * </pre> */ public class JettyServletExampleServer { private static final Logger LOGGER = LoggerFactory .getLogger(JettyServletExampleServer.class); /** * <pre> * @param args * </pre> */ public static void main(String[] args) { try { Server server = new Server(8080); ServletContextHandler context = new ServletContextHandler( ServletContextHandler.SESSIONS); context.setContextPath("/"); server.setHandler(context); context.addServlet(new ServletHolder(new SearchServlet()), "/search"); LOGGER.info("server start."); server.start(); server.join(); } catch (Exception e) { e.printStackTrace(); } } }
/** * <pre> * Copyright baidu.com CDC [2000-2014] * </pre> */ package test.servlet; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import test.utils.Tools; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * <pre> * HelloServlet.java * @author kanpiaoxue<br> * @version 1.0 * Create Time 2014年9月2日 下午4:55:40<br> * Description : HttpServlet * </pre> */ public class SearchServlet extends HttpServlet { private static final Logger LOGGER = LoggerFactory .getLogger(SearchServlet.class); /** * <pre> * </pre> */ private static final long serialVersionUID = -4012838481920999524L; /** * 写在这里的代码都是 POST 请求 */ @Override public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String query = request.getParameter("query"); LOGGER.info(String.format("receive query: %s", query)); String result = "welcome to my server. It's a POST request."; if (null != query && !query.trim().equals("")) { result = query + ", " + result; } LOGGER.info(String.format("response is: %s", result)); Tools.printToJson(result, response); } /** * 写在这里的代码都是 GET 请求 */ @Override public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String query = request.getParameter("query"); LOGGER.info(String.format("receive query: %s", query)); String result = "welcome to my server. It's a GET request."; if (null != query && !query.trim().equals("")) { result = query + ", " + result; } LOGGER.info(String.format("response is: %s", result)); Tools.printToJson(result, response); } }
package test.utils; import org.eclipse.jetty.server.Request; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.http.HttpServletResponse; /** * <pre> * Tools.java * @author kanpiaoxue<br> * @version 1.0 * Create Time 2014年9月2日 下午4:57:06<br> * Description : 工具类 * </pre> */ public class Tools { private Tools() { super(); } /** * <pre> * @param baseRequest * @param response * @param result 需要返回给客户的结果 * @throws IOException * 将结果 result 返回给客户 * </pre> */ public static void print(Request baseRequest, HttpServletResponse response, String result) throws IOException { response.setContentType("text/json;charset=utf-8"); response.setStatus(HttpServletResponse.SC_OK); baseRequest.setHandled(true); response.getWriter().println(result); } /** * 直接输出 json 字符串 * * @param json */ public static void printToJson(String json, HttpServletResponse response) { try { response.setCharacterEncoding("UTF-8"); response.setContentType("text/json"); response.setDateHeader("Expires", 0); PrintWriter out = response.getWriter(); out.print(json); out.flush(); out.close(); } catch (Exception e) { e.printStackTrace(); } } }
源码详见附件
我还有一篇问题,是用jetty和spring结合的:
嵌入jetty的springMVC可运行jar的REST+
关于嵌入式 jetty 更多的内容请参考: http://wiki.eclipse.org/Jetty/Tutorial/Embedding_Jetty