java - 无法创建 PoolableConnectionFactory (未知数据库 'database' )

Question

我正在尝试使用数据库创建 Web 应用程序，但收到此错误:

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？

如果需要，我可以发布代码。

上下文.xml

<?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>

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);
            }

        });        
});

});

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>

国家.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;
    }


}

国家信息.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;

    }   

}

Answer 1

对于我的情况，我只需从 context.xml 中的 url (url="jdbc:mysql://localhost:3306/web_student_tracker?useSSL=false") 中删除:“useSSL=false”，然后它就可以工作了。

context.xml

user page of student list