servletConfig的使用案例
servletConfig参数的使用案例
首先，建立Dynamic Web Project ，同样命名FirstServlet，然后建立Servlet:Login.java，包名为cc.openhome
做如下修改：
package cc.openhome;
import java.io.IOException; import java.io.PrintWriter;
import javax.servlet.ServletException; import javax.servlet.annotation.WebInitParam; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;
@WebServlet(
name="Login",
urlPatterns={"/login.do"},
initParams={
@WebInitParam(name = "SUCCESS", value = "success.jsp"),
@WebInitParam(name = "ERROR", value = "error.jsp")
}
)
public class Login extends HttpServlet {
private String SUCCESS_VIEW;
private String ERROR_VIEW;
@Override
public void init() throws ServletException {
SUCCESS_VIEW=getInitParameter("SUCCESS");
ERROR_VIEW=getInitParameter("ERROR");
}
@Override public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
String userName=request.getParameter("userName");
String password=request.getParameter("password");
if("caterpillar".equals(userName) && "123456".equals(password)){
request.getRequestDispatcher(SUCCESS_VIEW).forward(request, response);
}else{
request.getRequestDispatcher(ERROR_VIEW).forward(request, response);
}
}
.......//其余代码不赘述
}
先在WEB-INF下的web.xml内添加欢迎界面：
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
然后在WebRoot路径下，新建两个jsp页面，success.jsp和error.jsp。在这两个页面<body>内分别添加，<h1>登录成功！</h1>和<h1>登录失败！</h1>
在index.jsp添加如下内容：
<form method="post" action="<%=path%>/login.do">
<table>
<tr><td>用户名：</td><td><input type="text" name="userName" value=""/></td></tr>
<tr><td>密码：</td><td><input type="password" name="password" value=""/></td></tr>
<tr><td><input type="submit" value="登录"/></td><td></td></tr>
</table>
</form>
启动tomcat，打开浏览器，输入http://localhost:8080/FirstServlet/然后测试即可
至于@WebServlet中的内容，也可以卸载WEB-INF下的web.xml内，这样会覆盖掉webServlet内的初始参数:
<servlet>
<servlet-name>Login</servlet-name>
<servlet-class>cc.openhome.Login</servlet-class>
<init-param>
<param-name>SUCCESS</param-name>
<param-value>success.jsp</param-value>
</init-param>
<init-param>
<param-name>ERROR</param-name>
<param-value>error.jsp</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Login</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>
