如何通过Servlet类获取初始化参数

在web.xml中配置servlet时，可以配置一些初始化参数。而在servlet中能够通过ServletConfig接口提供的方法来取得这些参数。

1、在web.xml中配置初始化参数username：admin；password：12345

2、在index.jsp中添加超链接，超链接默认是get访问，但我们可以在doGet（）方法中添加doPost（），使其做post访问

public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doPost(request,response);
    }

3、在init（）方法中获得初始化参数

运行效果

最后贴出Servlet类代码

package servlet;

import java.io.IOException;
import java.io.PrintWriter;

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

public class GetInitParameterServlet extends HttpServlet {

    private String username;//用户名
    private String password; //密码



    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    /**
     * Constructor of the object.
     */
    public GetInitParameterServlet() {
        super();
    }

    /**
     * Destruction of the servlet. 

     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. 

     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doPost(request,response);
    }

    /**
     * The doPost method of the servlet. 

     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.println("");
        out.println("");
        out.println("  ");
        out.println("  ");
        out.println("
"+"用户名："+this.getUsername()+"
");
        out.println("
"+"密码："+this.getPassword()+"
");
        out.println("  ");
        out.println("");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. 

     *
     * @throws ServletException if an error occurs
     */
    //在init()方法中获得初始化参数
    public void init() throws ServletException {
        // 通过this.getInitParameter("要读取的参数名")
        //即可获得初始化参数，返回字符串类型
      this.setUsername(this.getInitParameter("username"));
      this.setPassword(this.getInitParameter("password"));
    }

}