Question

我是JSP新手并尝试创建一个Web应用程序，我可以从mysql db中检索一个actor列表并在JSP页面中填充它。

我成功地从mysql数据库中检索了actor（firstname，lastname，actor_id）并填充了一个actor arraylist对象但是无法在JSP页面中填充它，

这是我的代码，

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1" import="com.dbconnect.Actor,java.util.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>All the actors from SAKILA database</title>
</head>
<body> 
Im in get actors.jspp

<%ArrayList<Actor> acrs =  (ArrayList<Actor>)request.getAttribute("actorslist");%>
<c:forEach var="Actor"  items="${acrs}">
    FirstName:<c:out value="${Actor.getFirstname()}"></c:out>
</c:forEach>

%>

</body>
</html>

Servlet code


package com.dbconnect;

import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;

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

/**
 * Servlet implementation class actorservlet
 */
public class actorservlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public actorservlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("Im in actorsservlet");
        Actors acrs = new Actors();
        ArrayList<Actor> actorslist = null;
        try {
            actorslist = acrs.getactors();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        for (Actor ac:actorslist)
            System.out.println(ac.firstname);
        request.setAttribute("actorslist", actorslist);
        RequestDispatcher dispatcher = request.getRequestDispatcher("getactors.jsp");
        //response.sendRedirect("getactors.jsp");
        dispatcher.forward(request, response);
        return;
    }

}

Actors.java

package com.dbconnect;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class Actors {
    List<Actor> ls = new ArrayList<Actor>();
    DbContext db = null;
    Actors(){

        try {
            this.db = new DbContext();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public ArrayList<Actor> getactors() throws ClassNotFoundException,
            SQLException {

        ResultSet rs = this.db.getrows();
        populateactorlist(rs);
        return (ArrayList<Actor>) ls;
    }

    public void populateactorlist(ResultSet rs) throws SQLException {
        while (rs.next()) {
            Actor rc = new Actor();
            rc.setActor_id(rs.getInt("actor_id"));
            rc.setFirstname(rs.getString("first_name"));
            rc.setLastname(rs.getString("last_name"));
            ls.add(rc);
        }
    }


    }

}

Actor.java
package com.dbconnect;

public class Actor {
    Integer actor_id = null;
    String firstname = null;
    String lastname = null;

    public Integer getActor_id() {
        return actor_id;
    }

    public void setActor_id(Integer actor_id) {
        this.actor_id = actor_id;
    }

    public String getFirstname() {
        return firstname;
    }

    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

}

Answer 1

我不确定无关的标签。试试这个：

<% ArrayList<Actor> acrs =  (ArrayList<Actor>)request.getAttribute("actorslist"); %>
<c:forEach var="Actor"  items="${acrs}">
    FirstName:<c:out value="${Actor.getFirstname()}"/><br/>
</c:forEach>

特别是，删除较低的%>（拼写错误？）

jsp填充对象数组

1 个答案: