在前端页面调用sevlet的路径

1.路径：相对路径和绝对路径

<!-- 使用相对路径访问Servletpath -->
    <a href="servlet/ServletPath">这是Servlet</a>
    <!-- 使用绝对路径访问ServletPath，可以使用path变量，path变量表示根目录 -->
     <a href="<%=basePath%>/servlet/ServletPath">这是Servlet</a>

2.servlet高级

1.获取初始化参数

在web.xml中配置servlet时，可以获取一些初始化参数，而在servlet中可以通过servletConfig接口提供的方法得到这些参数。

在web.xml中加入如下信息：（在servlet标签中）尤其注意在init方法中写入的方法，使用了this

  <init-param>
        <param-name>username</param-name>
        <param-value>admin</param-value>
    </init-param>
      <init-param>
        <param-name>password</param-name>
        <param-value>123456</param-value>
    </init-param>

建立的GetInitPar.java中写入如下代码：

package sxy;

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 GetInitPar extends HttpServlet {
    
    private String username;
    private String password;

    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 GetInitPar() {
        super();
    }

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

        doPost(request,response);
    }

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

        response.setContentType("text/html");
        request.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        out.println("<h2>"+this.getUsername()+"</h2>");
        out.println("<h2>"+this.getPassword()+"</h2>");
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    public void init() throws ServletException {
        // Put your code here
        this.setUsername(this.getInitParameter("username"));
        this.setPassword(this.getInitParameter("passowrd"));
    }

}