访问Servlet的配置参数

Dear 丶 2021-07-24 13:31 363阅读 0赞

**一 控制器**

package lee;
    
    import java.sql.*;
    
    import javax.servlet.http.*;
    import javax.servlet.*;
    import javax.servlet.annotation.*;
    import java.io.*;
    
    
    @WebServlet(name="testServlet"
        , urlPatterns={"/testServlet"}
        , initParams={
            @WebInitParam(name="driver", value="com.mysql.jdbc.Driver"),
            @WebInitParam(name="url", value="jdbc:mysql://localhost:3306/javaee"),
            @WebInitParam(name="user", value="root"),
            @WebInitParam(name="pass", value="32147")})
    public class TestServlet extends HttpServlet
    {
        // 重写init方法
        public void init(ServletConfig config)
            throws ServletException
        {
            // 重写该方法，应该首先调用父类的init()方法
            super.init(config);
        }
        // 响应客户端请求的方法
        public void service(HttpServletRequest request,
            HttpServletResponse response)
            throws ServletException,java.io.IOException
        {
            try
            {
                // 获取ServletConfig对象
                ServletConfig config = getServletConfig();
                // 通过ServletConfig对象获取配置参数：dirver
                String driver = config.getInitParameter("driver");
                // 通过ServletConfig对象获取配置参数：url
                String url = config.getInitParameter("url");
                // 通过ServletConfig对象获取配置参数：user
                String user = config.getInitParameter("user");
                // 通过ServletConfig对象获取配置参数：pass
                String pass = config.getInitParameter("pass");
                // 注册驱动
                Class.forName(driver);
                // 获取数据库连接
                Connection conn = DriverManager.getConnection(url,user,pass);
                // 创建Statement对象
                Statement stmt = conn.createStatement();
                // 执行查询，获取ResuletSet对象
                ResultSet rs = stmt.executeQuery("select * from news_inf");
                response.setContentType("text/html;charSet=gbk");
                // 获取页面输出流
                PrintStream out = new PrintStream(response.getOutputStream());
                // 输出HTML标签
                out.println("<html>");
                out.println("<head>");
                out.println("<title>访问Servlet初始化参数测试</title>");
                out.println("</head>");
                out.println("<body>");
                out.println("<table bgcolor=\"#9999dd\" border=\"1\"" +
                    "width=\"480\">");
                // 遍历结果集
                while(rs.next())
                {
                    // 输出结果集内容
                    out.println("<tr>");
                    out.println("<td>" + rs.getString(1) + "</td>");
                    out.println("<td>" + rs.getString(2) + "</td>");
                    out.println("</tr>");
                }
                out.println("</table>");
                out.println("</body>");
                out.println("</html>");
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    }

**二 测试**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

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