我正在编写一个 Web 应用程序,其中有一个要使用 Ajax 生成的表。这些数据实际上是从数据库中提取的。下面是我的代码。
Index.jsp
<html>
<head>
</head>
<body>
<marquee>
<h1>This is an example of ajax</h1>
</marquee>
<form name="vinform">
Enter id:<input type="button" id="somebutton" value="Click Me">
</form>
<span id="somediv"> </span>
<script src="//code.jquery.com/jquery-1.10.2.js"></script>
<script src="//code.jquery.com/ui/1.10.4/jquery-ui.js"></script>
<script type="text/javascript" src="tableGenerator.js"></script>
</body>
</html>
tableGenerator.js
$('#somebutton').click(
function() {
$.getJSON('Controller', function(searchList) {
var $table = $('<table>').appendTo($('#somediv'));
$.each(searchList, function(index, userBean) {
$('<tr>').appendTo($table).append(
$('<td>').text(userBean.caseNumber)).append(
$('<td>').text(userBean.caseOwner)).append(
$('<td>').text(userBean.status)).append(
$('<td>').text(userBean.issue)).append(
$('<td>').text(userBean.reason)).append(
$('<td>').text(userBean.dateOpened));
});
});
});
UserBean.java
package org.bean;
public class UserBean {
private int age;
private String caseOwner, status, issue, reason, dateOpened, caseNumber, resolution, finalStatus, startDate,
endDate;
private Double totalTimeTaken;
public String getStartDate() {
return startDate;
}
public void setStartDate(String startDate) {
this.startDate = startDate;
}
public String getEndDate() {
return endDate;
}
public void setEndDate(String endDate) {
this.endDate = endDate;
}
public String getCaseNumber() {
return caseNumber;
}
public void setCaseNumber(String caseNumber) {
this.caseNumber = caseNumber;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getCaseOwner() {
return caseOwner;
}
public void setCaseOwner(String caseOwner) {
this.caseOwner = caseOwner;
}
public String getStatus() {
return status;
}
public String getReason() {
return reason;
}
public void setReason(String reason) {
this.reason = reason;
}
public void setStatus(String status) {
this.status = status;
}
public String getIssue() {
return issue;
}
public void setIssue(String issue) {
this.issue = issue;
}
public String getDateOpened() {
return dateOpened;
}
public void setDateOpened(String dateOpened) {
this.dateOpened = dateOpened;
}
public String getResolution() {
return resolution;
}
public void setResolution(String resolution) {
this.resolution = resolution;
}
public String getFinalStatus() {
return finalStatus;
}
public void setFinalStatus(String finalStatus) {
this.finalStatus = finalStatus;
}
public double getTotalTimeTaken() {
return totalTimeTaken;
}
public void setTotalTimeTaken(Double totalTimeTaken) {
this.totalTimeTaken = totalTimeTaken;
}
public UserBean() {
}
public UserBean(String caseNumber, String caseOwner, String issue, int age, String reason, String dateOpened,
String status, String finalStatus, String resolution, String startDate, String endDate,
Double totalTimeTaken) {
this.caseNumber = caseNumber;
this.caseOwner = caseOwner;
this.issue = issue;
this.reason = reason;
this.age = age;
this.dateOpened = dateOpened;
this.status = status;
this.resolution = resolution;
this.finalStatus = finalStatus;
this.startDate = startDate;
this.endDate = endDate;
this.totalTimeTaken = totalTimeTaken;
}
}
Controller.java(Servlet)
import java.io.IOException;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.bean.UserBean;
import com.dao.DataDao;
import com.google.gson.Gson;
@WebServlet("/Controller")
public class Controller extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
// String id = request.getParameter("val");
DataDao dataDao = new DataDao();
ArrayList<UserBean> list = dataDao.getFrameWork();
String searchList = new Gson().toJson(list);
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(searchList);
} catch (Exception e) {
System.err.println(e.getMessage());
}
}
}
DBUtility.java
package com.dao;
import java.sql.Connection;
import java.sql.DriverManager;
public class DBUtility {
private static Connection connection = null;
public static Connection getConnection() throws Exception {
if (connection != null)
return connection;
else {
// Store the database URL in a string
String userName = "sa";
String password = "T!ger123";
String url = "jdbc:sqlserver:XXXXXX;DatabaseName=TEST";
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
// set the url, username and password for the databse
connection = DriverManager.getConnection(url, userName, password);
return connection;
}
}
}
DataDao.java
package com.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import org.bean.UserBean;
public class DataDao {
private Connection connection;
public DataDao() throws Exception {
connection = DBUtility.getConnection();
}
public ArrayList<UserBean> getFrameWork() throws SQLException {
ArrayList<UserBean> list = new ArrayList<UserBean>();
PreparedStatement ps = null;
try {
ps = connection.prepareStatement("select * from statusTable");
// ps.setString(1, frameWork);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
UserBean userBean = new UserBean();
userBean.setCaseNumber(rs.getString(1));
userBean.setCaseOwner(rs.getString(2));
userBean.setStatus(rs.getString(3));
userBean.setIssue(rs.getString(4));
userBean.setReason(rs.getString(5));
userBean.setDateOpened(rs.getString(6));
userBean.setAge(rs.getInt(7));
list.add(userBean);
}
} catch (Exception e) {
System.out.println(e.getMessage());
}
return list;
}
}
我刚开始使用 Ajax/Jquery/JSON 技术。我已经按照教程 How to use Servlets and Ajax? 进行操作作者:@BalusC。
这里我有 2 个疑问。
当我将下面的 block 放入
<head>
时,它不起作用。<script src="//code.jquery.com/jquery-1.10.2.js"></script> <script src="//code.jquery.com/ui/1.10.4/jquery-ui.js"></script> <script type="text/javascript" src="tableGenerator.js"></script>
当我将上面相同的代码放入
<body>
时,它向我抛出以下异常。将 varchar 值转换为 JDBC 数据类型 INTEGER 时出错。
当我做了sp_help statusTable
时(这是相当于 Oracle 的 desc statusTable
的 sqlserver 查询)。我得到的结果如下面的屏幕截图所示。
无法理解哪里存在数据类型不匹配。
请让我知道我哪里出了问题以及如何解决。
谢谢
最佳答案
SQL Server 列出的列顺序与 JDBC 结果集中的列顺序之间似乎不匹配。特别是,第 7 列似乎与 Age
列不对应。
要检查哪个列名对应哪个列号,您可以使用结果集的元数据:
ResultSetMetaData meta = rs.getMetaData();
String name = meta.getColumnName(7);
这可能是更明智的选择:
- 在查询中显式列出列名称,而不是使用
SELECT *
;或 - 通过指定列名称而不是索引号来检索数据。
关于您的第一个问题,如果您将 Javascript 放在 header 中,则 #somebutton
clickhandler 会在元素加载到 DOM 之前实例化,因此它不起作用。
关于jquery - jsp中抛出的数据类型异常,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34651581/