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她与晚风 发表于 2023-4-24 16:21:26

js

            writer.println("    <tr>\n" +
                     "          <td>" + department_id + "</td>\n" +
                     "          <td>" + department_name + "</td>\n" +
                     "          <td>" + manager_id +"</td>\n" +
                     "          <td>"+ City + "</td>\n" +
                     "          <td><a href=\"/Servlet4/dept/detail?department_id="+department_id + "\" target=\"_black\">详情</a></td>\n"+
                     "          <td><a href='javascript:void(0)' onclick='del(" + department_id + ")'>删除</a></td>\n"+
                     "          <td><a href='javascript:void(0)' onclick='Update(" + City + ")'>修改</a></td>\n"+
                     "    </tr>");

有颜色的那一行代码点击后无法执行语句
如果把City换为department_id就可以执行
两个都是String类型

她与晚风 发表于 2023-4-24 16:23:19

界面
修改点后无反应,换成department_id就有反应

wp231957 发表于 2023-4-24 16:27:29

她与晚风发表于 2023-4-24 16:23
界面
修改点后无反应,换成department_id就有反应

把全部代码打包发出来吧

她与晚风 发表于 2023-4-24 16:33:29

本帖最后由她与晚风于 2023-4-24 16:36 编辑

wp231957 发表于 2023-4-24 16:27
把全部代码打包发出来吧

package coco;

import jakarta.servlet.ServletException;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

public class DeptListServletDemo extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
   System.out.println("-------------------------------");
   resp.setContentType("text/html");
   PrintWriter writer = resp.getWriter();
   writer.println(" <script>\n" +
            "    function del(department_id){\n" +
            "          var bool = window.confirm('确定删除吗?');\n" +
            "          if(bool){\n" +
            "             alert('ok,正在执行删除操作');\n" +
            "             document.location.href='/Servlet4/dept/delete?department_id=' + department_id;\n" +
            "          }else {\n" +
            "             alert('好的,已取消操作');\n" +
            "          }\n" +
            "    };\n" );
            writer.println("    function Update(city){\n" +
            "          var bool = window.confirm('确定要修改吗?');\n" +
            "          if(bool){\n" +
            "             var key = prompt('请输入要修改的属性名称:');\n" +
            "             var value = prompt('请输入新的' + key + ':');\n" +
            "             if(key == 'department_name'){\n" +
            "\n" +
            "             }else if(key == 'manager_id'){\n" +
            "\n" +
            "             }else if(key == 'city'){\n" +
            "                document.location.href='/Servlet4/dept/update?city1=' + city + '&city2=' + value;\n" +
            "             }\n" +
            "             else {\n" +
            "                alert('输入参数错误')\n" +
            "             }\n" +
            "          }\n" +
            "    }\n" +
            " </script>");
   writer.println("<h1 align=\"center\">welcome dept html</h1>\n" +
            " <table border=\"1px\" cellpadding=\"30px\" cellspacing=\"0\">\n" +
            "    <tr>\n" +
            "          <th>Department_id</th>\n" +
            "          <th>Department_name</th>\n" +
            "          <th>Manager_id</th>\n" +
            "          <th>City</th>\n" +
            "          <th colspan='3'>Function</th>\n" +
            "    </tr>");

   Connection connection = null;
   PreparedStatement preparedStatement = null;
   ResultSet resultSet = null;
   try{
         Class.forName("com.mysql.cj.jdbc.Driver");
         connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/myemployees","root","123456");
         preparedStatement = connection.prepareStatement("select department_id,department_name,manager_id,city from departments a left join locations b on a.location_id=b.location_id");
         resultSet = preparedStatement.executeQuery();
         while (resultSet.next()){
            String department_id = resultSet.getString("department_id");
            String department_name = resultSet.getString("department_name");
            String manager_id = resultSet.getString("manager_id");
            String City = resultSet.getString("city");
            writer.println("    <tr>\n" +
                     "          <td>" + department_id + "</td>\n" +
                     "          <td>" + department_name + "</td>\n" +
                     "          <td>" + manager_id +"</td>\n" +
                     "          <td>"+ City + "</td>\n" +
                     "          <td><a href=\"/Servlet4/dept/detail?department_id="+department_id + "\" target=\"_black\">详情</a></td>\n"+
                     //"          <td><a href='#' onclick='del(" + department_id + ")'>删除</a></td>\n"+
               "          <td><a href='javascript:void(0)' onclick='Update(" + City + ")'>修改</a></td>\n"+
                     "    </tr>");

         }
   } catch (ClassNotFoundException e) {
         throw new RuntimeException(e);
   } catch (SQLException e) {
         throw new RuntimeException(e);
   }
   writer.println("</table>");
}
}

她与晚风 发表于 2023-4-24 16:34:54

wp231957 发表于 2023-4-24 16:27
把全部代码打包发出来吧

这个限制发送大小发不过去,问题出在script Update函数下应该是,其它都正常

她与晚风 发表于 2023-4-24 16:35:29

wp231957 发表于 2023-4-24 16:27
把全部代码打包发出来吧

这个链接点不了

isdkz 发表于 2023-4-24 16:37:22

本帖最后由 isdkz 于 2023-4-24 16:40 编辑

问题的根本原因在于 `onclick` 事件传递参数的方式。当传递 `City` 参数时，它没有被引号包围，因此浏览器无法正确解析。为了解决这个问题，需要在将 `City` 传递给 `Update()` 函数时使用引号将其包围。这样，当 `City` 是一个字符串时，浏览器将能正确解析它。修改后的代码如下：

writer.println("    <tr>\n" +
   "          <td>" + department_id + "</td>\n" +
   "          <td>" + department_name + "</td>\n" +
   "          <td>" + manager_id +"</td>\n" +
   "          <td>"+ City + "</td>\n" +
   "          <td><a href=\\"/Servlet4/dept/detail?department_id="+department_id + "\\" target=\\"_black\\">详情</a></td>\n"+
   "          <td><a href='javascript:void(0)' onclick='del(" + department_id + ")'>删除</a></td>\n"+
   "          <td><a href='javascript:void(0)' onclick='Update(\\"" + City + "\\")'>修改</a></td>\n"+
   "    </tr>");

注意，在 `onclick='Update(\"" + City + "\")'` 部分，我们使用了转义字符 `\` 来在单引号内包含双引号。这将确保 `City` 作为字符串参数传递给 `Update()` 函数。现在，点击修改链接应该可以正确执行 `Update()` 函数。

她与晚风 发表于 2023-4-24 16:38:50

isdkz 发表于 2023-4-24 16:37
问题的根本原因在于 `onclick` 事件传递参数的方式。当传递 `City` 参数时，它没有被引号包围，因此浏览器 ...

city本身就是一个字符串

她与晚风 发表于 2023-4-24 16:39:23

isdkz 发表于 2023-4-24 16:37
问题的根本原因在于 `onclick` 事件传递参数的方式。当传递 `City` 参数时，它没有被引号包围，因此浏览器 ...

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script>
   function del(department_id){
         var bool = window.confirm('确定删除吗?');
         if(bool){
            alert('ok,正在执行删除操作');
            document.location.href='/Servlet4/dept/delete?department_id=' + department_id;
         }else {
            alert('好的,已取消操作');
         }
   }
   function update(city){
         alert(typeof city);
         /*
         var bool = window.confirm('确定要修改吗?');
         if(bool){
            var key = prompt('请输入要修改的属性名称:');
            var value = prompt('请输入新的' + key + ':');
            if(key == 'department_name'){

            }else if(key == 'manager_id'){

            }else if(key == 'city'){
               document.location.href='/Servlet4/dept/update?city1=' + city + '&city2=' + value;
            }
            else {
               alert('输入参数错误')
            }
         }*/
   }
</script>
</head>
<body>
<a href="javascript:void(0)" onclick="update('hjk')">s</a>
<a href="javascript:void(0)" onclick="del(2)">s</a>
</body>
</html>

她与晚风 发表于 2023-4-24 16:40:09

isdkz 发表于 2023-4-24 16:37
问题的根本原因在于 `onclick` 事件传递参数的方式。当传递 `City` 参数时，它没有被引号包围，因此浏览器 ...

我单拿到html页面里面没问题,一放到Servlet里面就执行不了了

isdkz 发表于 2023-4-24 16:43:13

她与晚风发表于 2023-4-24 16:40
我单拿到html页面里面没问题,一放到Servlet里面就执行不了了

根据您提供的完整 HTML 代码，我没有发现任何问题。然而，您提到在将其放入 Servlet 中时，代码无法正常执行。这可能是由于在将 HTML 代码插入 Servlet 时出现了问题。以下是使用 `PrintWriter` 将 HTML 代码插入 Servlet 的示例：

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {

   response.setContentType("text/html;charset=UTF-8");
   PrintWriter out = response.getWriter();

   out.println("<!DOCTYPE html>");
   out.println("<html lang=\\"en\\">");
   out.println("<head>");
   out.println(" <meta charset=\\"UTF-8\\">");
   out.println(" <title>Title</title>");
   out.println(" <script>");
   // 注意：在这里插入 JavaScript 代码
   out.println(" </script>");
   out.println("</head>");
   out.println("<body>");
   // 注意：在这里插入其他 HTML 代码
   out.println("</body>");
   out.println("</html>");

   out.close();
}
}

请确保您已正确插入 JavaScript 和 HTML 代码。如果仍然无法正常执行，请检查以下方面：

1. 确保 Servlet 配置正确。请检查 `web.xml` 文件，确保 Servlet 映射正确。
2. 检查浏览器的开发者控制台，查看是否有 JavaScript 错误或其他相关错误。
3. 清除浏览器缓存，确保加载的是最新的 Servlet 输出。

如果问题仍然存在，请提供更多关于您的 Servlet 代码和配置的详细信息，以便我能更好地帮助您解决问题。

她与晚风 发表于 2023-4-24 19:08:21

isdkz 发表于 2023-4-24 16:37
问题的根本原因在于 `onclick` 事件传递参数的方式。当传递 `City` 参数时，它没有被引号包围，因此浏览器 ...

package coco;

import jakarta.servlet.ServletException;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

public class DeptListServletDemo extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
   resp.setContentType("text/html");
   PrintWriter writer = resp.getWriter();
   writer.println("<!DOCTYPE html>");
   writer.println("<html lang=\"en\">");
   writer.println("<head>");
   writer.println("<meta charset=\"UTF-8\">");
   writer.println(" <title>Title</title>");
   writer.println(" <script>");
   writer.println("    function update(city1){");
   writer.println("          var city2 = prompt('请输入修改后的城市名:');");
   writer.println("          if(window.confirm('你确定要将' + city1 + '修改为' + city2 + '吗?')){");
   writer.println("             alert('ok,正在执行操作');");
   writer.println("             document.location.href='/Servlet4/dept/update?city1=' + city1 + 'city2=' + city2;");
   writer.println("          }else {");
   writer.println("             alert('取消成功');");
   writer.println("          }");
   writer.println("    }");
   writer.println("    function Delete(department_id){");
   writer.println("          if(window.confirm('确定要执行删除操作吗?')){");
   writer.println("             alert('Ok,正在执行删除操作');");
   writer.println("             document.location.href='/Servlet4/dept/delete?department_id='+'department_id'");
   writer.println("          }else {");
   writer.println("             alert('已确认取消');");
   writer.println("          }");
   writer.println("    }");
   writer.println(" </script>");

   writer.println("</head>");

   writer.println("<body>");
   writer.println("    <table border='1px' cellspacing='0' cellpadding='30px'>");
   writer.println("    <tr>");
   writer.println("          <th>department_id</th>");
   writer.println("          <th>department_name</th>");
   writer.println("          <th>manager_id</th>");
   writer.println("          <th>city</th>");
   writer.println("          <th colspan='3'>Function</th>");
   writer.println("    </tr>");

         Connection connection = null;
         PreparedStatement preparedStatement = null;
         ResultSet resultSet = null;
         try{
            Class.forName("com.mysql.cj.jdbc.Driver");
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/myemployees","root","123456");
            preparedStatement = connection.prepareStatement("select department_id,department_name,manager_id,cityfrom departments a left join locations b on a.location_id=b.location_id");
            resultSet = preparedStatement.executeQuery();
            while (resultSet.next()){
               String department_id = resultSet.getString("department_id");
               String department_name = resultSet.getString("department_name");
               String manager_id = resultSet.getString("manager_id");
               String City = resultSet.getString("city");
            writer.println("    <tr>");
            writer.println("          <td>"+ department_id +"</td>");
            writer.println("          <td>"+ department_name +"</td>");
            writer.println("          <td>"+ manager_id +"</td>");
            writer.println("          <td>"+ City +"</td>");

               writer.println("          <td><a href='javascript:void (0)' onclick= 'Delete(" +department_id+")' target='_black'>update</a></td>>");
               writer.println("          <td><a href='javascript:void (0)' onclick= 'update("+City+")' target='_black'>delete</a></td>");
               writer.println("          <td><a href='/Servlet4/dept/detail?department_id=' + " + department_id +" target='_black'>详情</a></td>");
               writer.println("    </tr>");
         }
   } catch (ClassNotFoundException e) {
         throw new RuntimeException(e);
   } catch (SQLException e) {
         throw new RuntimeException(e);
   }
   writer.println(" </table>");
   writer.println("</body>");
   writer.println("</html>");
}
}

她与晚风 发表于 2023-4-24 19:09:18

isdkz 发表于 2023-4-24 16:43
根据您提供的完整 HTML 代码，我没有发现任何问题。然而，您提到在将其放入 Servlet 中时，代码无法正常 ...

放这个里面还是有问题,不知道错哪里了

isdkz 发表于 2023-4-24 19:12:52

她与晚风发表于 2023-4-24 19:09
放这个里面还是有问题,不知道错哪里了

我发现了一个问题，您在 `onclick` 属性中传递给 `update` 函数的 `City` 参数没有用引号包围。请尝试将以下代码行：

writer.println("          <td><a href='javascript:void (0)' onclick= 'update("+City+")' target='_black'>delete</a></td>");

更改为：

writer.println("          <td><a href='javascript:void (0)' onclick= 'update(\\""+City+"\\")' target='_black'>delete</a></td>");

同时，还需要修改以下这行代码：

writer.println("          <td><a href='javascript:void (0)' onclick= 'Delete(" +department_id+")' target='_black'>update</a></td>>");

将 `update` 改为 `delete` 并去掉多余的尖括号：

writer.println("          <td><a href='javascript:void (0)' onclick= 'Delete(" +department_id+")' target='_black'>delete</a></td>");

这应该解决您遇到的问题。请确保在传递字符串参数时使用引号包围参数。如果问题仍然存在，请提供更多详细信息，以便我可以进一步帮助您。

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