Курс Java-2016. Занятие 11. Servlets, JSP

Курс по Java, 2016

Servlet, JSP


Servlet API


javax.servlet.Servletimport javax.servlet.GenericServlet;

public class MyServlet extends GenericServlet { @Override public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException { // do something }}


javax.servlet.ServletRequestString remoteAddress = servletRequest.getRemoteAddr();String contentType = servletRequest.getContentType();InputStream input = servletRequest.getInputStream();String parameter = servletRequest.getParameter("name");Object attribute = servletRequest.getAttribute("name");servletRequest.setAttribute("name", attribute);


javax.servlet.ServletResponseservletResponse.setContentType("text/html");servletResponse.setContentLength(256);OutputStream output = servletResponse.getOutputStream();


javax.servlet.http.HttpServletpublic class MyHttpServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // process GET request } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // process POST request } }


javax.servlet.http.HttpServletRequestString remoteAddress = request.getRemoteAddr();String contentType = request.getContentType();Reader reader = request.getReader();String parameter = request.getParameter("name");Object attribute = request.getAttribute("name");request.setAttribute("name", attribute);Cookie[] cookies = request.getCookies();String proxiedClient = request.getHeader("X-Forwarded-For");HttpSession session = request.getSession();


javax.servlet.http.HttpSessionHttpSession session = request.getSession();

Object sessionAttribute = session.getAttribute("name");session.setAttribute("name", sessionAttribute);


javax.servlet.http.HttpServletResponseresponse.setContentType("text/html");response.setContentLength(256);Writer writer = response.getWriter();response.addCookie(new Cookie("name", "value"));response.addHeader("X-My-Header", "value");response.sendError(500, "Everything failed");response.sendRedirect("/other-path");


Servlet Container


Apache TomcatСамый популярный Servlet/JSP контейнерhttps://tomcat.apache.org/


$CATALINA_HOME├── bin├── conf├── lib├── logs├── webapps│ ├── hello│ │ ├── index.jsp│ │ ├── META-INF│ │ └── WEB-INF│ │ ├── classes│ │ │ └── it│ │ │ └── sevenbits│ │ │ └── example│ │ │ └── hello│ │ │ └── HelloWorldServlet.class│ │ └── web.xml│ ├── hello.war│ └── ROOT└── work


WARWeb Application aRchive

│ ├── hello.war│ │ ├── index.jsp│ │ ├── META-INF│ │ └── WEB-INF│ │ ├── classes│ │ │ └── it│ │ │ └── sevenbits│ │ │ └── example│ │ │ └── hello│ │ │ └── HelloWorldServlet.class│ │ └── web.xml


War в Maven<project> <modelVersion>4.0.0</modelVersion> <groupId>it.sevenbits.example</groupId> <artifactId>hello</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>hello Maven Webapp</name> <url>http://maven.apache.org</url> <build> <finalName>hello</finalName> </build></project>


Webapp в Maven <dependencies> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency> </dependencies>


Webapp в Maven


web.xml<web-app> <display-name>Sample Web Application</display-name> <servlet> <servlet-name>HelloWorldServlet</servlet-name> <servlet-class> it.sevenbits.example.hello.HelloWorldServlet </servlet-class> </servlet> <servlet-mapping> <servlet-name>HelloWorldServlet</servlet-name> <url-pattern>/world</url-pattern> </servlet-mapping></web-app>


Сборка веб приложенияmvn package

cp target/hello.war $CATALINA_HOME/webapps


HelloWorldServletpublic class HelloWorldServlet extends HttpServlet {

@Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/plain"); PrintWriter out = response.getWriter(); out.println("Hello, world"); }

}


JSPJava Server Pages

Servlet наоборот


hello_world.jsp<!DOCTYPE html><html><head> <title>Hello</title></head><body> <h1>Hello, world!</h1></body></html>


Model — View — Controller

MVC


Model● Атрибуты запроса● Сессия


ViewJSP

<!DOCTYPE html><html><head> <title>Hello <%=request.getAttribute("name")%></title></head><body> <h1>Hello, <%=request.getAttribute("name")%>!</h1></body></html>


ControllerServlet

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // model manipulations String name = request.getParameter("name"); request.setAttribute("name", name); // forward to view RequestDispatcher dispatcher = request.getRequestDispatcher("hello_name.jsp"); dispatcher.forward(request, response); }


Forward RequestDispatcher.forward(request, response)


Redirect HttpServlerResponse.sendRedirect(“path”)


J2EE


Домашнее заданиеПоставить Tomcat.

Сделать простое веб приложение с отправкой формы.

Посмотреть, в какой java код превращаются JSP страницы.

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Курс Java-2016. Занятие 11. Servlets, JSP

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