Servlet (二)ServletContext
package cn.sasa.serv; import java.io.IOException; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ContextServlet extends HttpServlet { private static final long serialVersionUID = 1L; public ContextServlet() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获得全局初始化参数 ServletContext context = this.getServletContext(); String url = context.getInitParameter("url"); System.out.println(url); //取得绝对路径getRealPath() String path1 = context.getRealPath("index.html"); System.out.println(path1); // String path = context.getRealPath("WEB-INF/classes/c3p0-config.xml"); // System.out.println(path); //classes下的文件 String path = ContextServlet.class.getClassLoader().getResource("c3p0-config.xml").getPath(); System.out.println(path); //ServletContext是全局的,可以获取另一个Servlet设置的值 int count = (int)context.getAttribute("count"); System.out.println(count); response.getWriter().append("Served at: ").append(request.getContextPath()); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package cn.sasa.serv; import java.io.IOException; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler; import cn.sasa.domain.MyUser; import cn.sasa.utils.C3P0Utils; public class Login extends HttpServlet { private static final long serialVersionUID = 1L; public Login() { super(); } public void init(){ //初始化时创建一个变量 int count = 0; this.getServletContext().setAttribute("count", count); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String userName = request.getParameter("userName"); String pwd = request.getParameter("pwd"); //System.out.println(userName+"====="+pwd); QueryRunner query = new QueryRunner(C3P0Utils.getDataSource()); String sql = "select * from user where name=? and pwd=?"; MyUser user = null; try { user = query.query(sql, new BeanHandler<MyUser>(MyUser.class), userName,pwd); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(user != null) { int count = (int)this.getServletContext().getAttribute("count"); count++; this.getServletContext().setAttribute("count", count); response.getWriter().write(user.toString()+"==="+count); }else { response.getWriter().write("wrong"); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }