我正在尝试使用数据库创建一个Web应用程序，我收到此错误：
org.apache.tomcat.dbcp.dbcp.SQLNestedException：无法创建PoolableConnectionFactory（未知数据库'数据库'）
有什么想法吗？
如有必要，我可以发布代码。
context.xml中
<?xml version="1.0" encoding="UTF-8"?>
<Context reloadable="true">
<Resource auth="Container"
name="jdbc/mysql"
type="javax.sql.DataSource"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/database"
username="root"
password="********" //I blocked the password
maxIdle="10"
maxActive="200"
maxWait="5"
removeAbandoned="true"
removeAbandonedTimeout="1200"
/>
</Context>
的web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">
<display-name>webApp-01</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<description>Get Information about Country - jQuery Ajax Request</description>
<display-name>CountryInformation</display-name>
<servlet-name>CountryInformation</servlet-name>
<servlet-class>com.as400samplecode.CountryInformation</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CountryInformation</servlet-name>
<url-pattern>/CountryInformation</url-pattern>
</servlet-mapping>
app.js
$(document).ready(function() {
//Stops the submit request
$("#myAjaxRequestForm").submit(function(e){
e.preventDefault();
});
//checks for the button click event
$("#myButton").click(function(e){
//get the form data and then serialize that
dataString = $("#myAjaxRequestForm").serialize();
//get the form data using another method
var countryCode = $("input#countryCode").val();
dataString = "countryCode=" + countryCode;
//make the AJAX request, dataType is set to json
//meaning we are expecting JSON data in response from the server
$.ajax({
type: "POST",
url: "CountryInformation",
data: dataString,
dataType: "json",
//if received a response from the server
success: function( data, textStatus, jqXHR) {
//our country code was correct so we have some information to display
if(data.success){
$("#ajaxResponse").html("");
$("#ajaxResponse").append("<b>Country Code:</b> " + data.countryInfo.code + "");
$("#ajaxResponse").append("<b>Country Name:</b> " + data.countryInfo.name + "");
$("#ajaxResponse").append("<b>Continent:</b> " + data.countryInfo.continent + "");
$("#ajaxResponse").append("<b>Region:</b> " + data.countryInfo.region + "");
$("#ajaxResponse").append("<b>Life Expectancy:</b> " + data.countryInfo.lifeExpectancy + "");
$("#ajaxResponse").append("<b>GNP:</b> " + data.countryInfo.gnp + "");
}
//display error message
else {
$("#ajaxResponse").html("<div><b>Country code in Invalid!</b></div>");
}
},
//If there was no resonse from the server
error: function(jqXHR, textStatus, errorThrown){
console.log("Something really bad happened " + textStatus);
$("#ajaxResponse").html(jqXHR.responseText);
},
//capture the request before it was sent to server
beforeSend: function(jqXHR, settings){
//adding some Dummy data to the request
settings.data += "&dummyData=whatever";
//disable the button until we get the response
$('#myButton').attr("disabled", true);
},
//this is called after the response or error functions are finsihed
//so that we can take some action
complete: function(jqXHR, textStatus){
//enable the button
$('#myButton').attr("disabled", false);
}
});
});
});
的index.html
<html>
<head>
<title>jQuery Ajax POST data Request and Response Example</title>
<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css" />
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js" type="text/javascript"></script>
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js" type="text/javascript"></script>
<script type="text/javascript" src="app.js"></script>
</head>
<body>
<form id="myAjaxRequestForm">
<fieldset>
<legend>jQuery Ajax Form data Submit Request</legend>
<p>
<label for="countryCode">Country Code:</label>
<input id="countryCode" type="text" name="countryCode" />
</p>
<p>
<input id="myButton" type="button" value="Submit" />
</p>
</fieldset>
</form>
<div id="anotherSection">
<fieldset>
<legend>Response from jQuery Ajax Request</legend>
<div id="ajaxResponse"></div>
</fieldset>
</div>
</body>
</html>
country.java
package com.as400samplecode;
public class Country {
String code = null;
String name = null;
String continent = null;
String region = null;
String lifeExpectancy = null;
String gnp = null;
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getContinent() {
return continent;
}
public void setContinent(String continent) {
this.continent = continent;
}
public String getRegion() {
return region;
}
public void setRegion(String region) {
this.region = region;
}
public String getLifeExpectancy() {
return lifeExpectancy;
}
public void setLifeExpectancy(String lifeExpectancy) {
this.lifeExpectancy = lifeExpectancy;
}
public String getGnp() {
return gnp;
}
public void setGnp(String gnp) {
this.gnp = gnp;
}
}
CountryInformation.java
package com.as400samplecode;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;
import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
public class CountryInformation extends HttpServlet {
private static final long serialVersionUID = 1L;
public CountryInformation() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String countryCode = request.getParameter("countryCode");
PrintWriter out = response.getWriter();
response.setContentType("text/html");
response.setHeader("Cache-control", "no-cache, no-store");
response.setHeader("Pragma", "no-cache");
response.setHeader("Expires", "-1");
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "POST");
response.setHeader("Access-Control-Allow-Headers", "Content-Type");
response.setHeader("Access-Control-Max-Age", "86400");
Gson gson = new Gson();
JsonObject myObj = new JsonObject();
Country countryInfo = getInfo(countryCode);
JsonElement countryObj = gson.toJsonTree(countryInfo);
if(countryInfo.getName() == null){
myObj.addProperty("success", false);
}
else {
myObj.addProperty("success", true);
}
myObj.add("countryInfo", countryObj);
out.println(myObj.toString());
out.close();
}
//Get Country Information
private Country getInfo(String countryCode) {
Country country = new Country();
Connection conn = null;
PreparedStatement stmt = null;
String sql = null;
try {
Context ctx = (Context) new InitialContext().lookup("java:comp/env");
conn = ((DataSource) ctx.lookup("jdbc/mysql")).getConnection();
sql = "Select * from COUNTRY where code = ?";
stmt = conn.prepareStatement(sql);
stmt.setString(1, countryCode.trim());
ResultSet rs = stmt.executeQuery();
while(rs.next()){
country.setCode(rs.getString("code").trim());
country.setName(rs.getString("name").trim());
country.setContinent(rs.getString("continent").trim());
country.setRegion(rs.getString("region").trim());
country.setLifeExpectancy(rs.getString("lifeExpectancy").trim());
country.setGnp(rs.getString("region").trim());
// country.setLifeExpectancy(rs.getString("lifeExpectancy") == null ? new Double(0) : Double.parseDouble(rs.getString("lifeExpectancy").trim()));
// country.setGnp(rs.getString("gnp") == null ? new Double(0) : Double.parseDouble(rs.getString("gnp").trim()));
}
rs.close();
stmt.close();
stmt = null;
conn.close();
conn = null;
}
catch(Exception e){System.out.println(e);}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException sqlex) {
// ignore -- as we can't do anything about it here
}
stmt = null;
}
if (conn != null) {
try {
conn.close();
} catch (SQLException sqlex) {
// ignore -- as we can't do anything about it here
}
conn = null;
}
}
return country;
}
}
答案 0 :(得分：0)
根据您收到的例外情况
无法创建PoolableConnectionFactory（未知数据库'数据库'）
...并将其与您传入的网址字符串进行比较
URL = “JDBC：MySQL的：//本地主机：3306 /数据库”
名为“database”的数据库不存在。
答案 1 :(得分：0)
对于我来说，我只是从context.xml中的URL（url =“ jdbc：mysql：// localhost：3306 / web_student_tracker？useSSL = false”）中删除“ useSSL = false”，然后它可以工作。
