标签：mysql servlets tomcat8

参见英文答案 > jdbc to MYSQL error: No suitable driver found for jdbc:mysql://localhost:3306/test?user=’root’&password=”                                     1个
我把mysql驱动程序放在… / ROOT / WEB-INF / lib和Tomcat 8.0 / lib中,但它没有效果.我正在使用以下类连接到DB：

package db;

import java.sql.*;

public class ConnectToDB implements AutoCloseable {
    Connection con;

    public ConnectToDB(String server, String database, String user,
            String password) throws SQLException {
        con = DriverManager.getConnection("jdbc:mysql://" + server + "/"
                + database, user, password);
    }

    @Override
    public void close() throws SQLException {
        con.close();
    }

    public Connection getConnection() {
        return con;
    }

}

Eclipse项目中包含以下类：

1. src / nr3 / model

package nr3.model;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import db.ConnectToDB;
public class MusikkHandler {
    private ConnectToDB db;
    private Connection con;
    private String tableName;
    private PreparedStatement pstmtGetRows;

    public MusikkHandler(String server, String database, String user,
            String password) throws SQLException {
        db = new ConnectToDB(server, database, user, password);
        con = db.getConnection();
        tableName = "album";
    }

    public void close() throws SQLException {
        db.close();
    }

    public ArrayList<Album> getRows(String genre) throws SQLException {
        ArrayList<Album> list = new ArrayList<Album>();
        pstmtGetRows = con.prepareStatement("SELECT * FROM " + tableName
                + " WHERE SJANGER = ?");
        pstmtGetRows.setString(1, genre);
        ResultSet rs = pstmtGetRows.executeQuery();
        while (rs.next()) {
            list.add(new Album(rs.getString(1), rs.getString(2), rs.getInt(3),
                    rs.getInt(4), rs.getString(5)));
        }
        rs.close();
        pstmtGetRows.close();
        return list;
    }
}

–

package nr3.model;

public class Album {
    private String tittel;
    private String artist;
    private int spor;
    private int utgitt;
    private String sjanger;

    public Album (String artist, String tittel, int spor, int utgitt, String sjanger){
        setArtist(artist);
        setTittel(tittel);
        setUtgitt(utgitt);
        setSpor(spor);
        setSjanger(sjanger);
    }
    public Album(){
        this(null, null, 0, 0, null);
    }
    public void setTittel(String tittel){
        this.tittel = tittel;
    }
    public void setArtist(String artist){
        this.artist = artist;
    }
    public void setSpor(int spor) {
        this.spor = spor;
    }
    public void setUtgitt(int utgitt) {
        this.utgitt = utgitt;
    }
    public void setSjanger(String sjanger) {
        this.sjanger = sjanger;
    }
    public String getTittel() {
        return tittel;
    }
    public String getArtist() {
        return artist;
    }
    public int getSpor() {
        return spor;
    }
    public int getUtgitt() {
        return utgitt;
    }
    public String getSjanger() {
        return sjanger;
    }
    public String toString(){
        return getTittel() + " (" + getArtist() + ")" + " Utgitt: " 
                                               + getUtgitt(); 
    }
}

2. src / nr3 / servlets

package nr3.servlets;

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

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

import nr3.model.Album;
import nr3.model.MusikkHandler;

public class MusikkValg extends HttpServlet {

    private static final long serialVersionUID = 428937262021570370L;

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String genre = request.getParameter("sjanger");
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        MusikkHandler mh;

        out.println("<html>");
        out.println("<head>");
        out.println("<title>Musikk</title>");
        out.println("</head>");
        out.println("<body>");
        out.println("<h1>MUSIKK-ANBEFALINGER</h1>");
        out.println("<br/>");
        out.println("<br/>");
        out.println("<h3>Da bør du kanskje forsøke en av disse:</h3>");
        out.println("<br/>");
        out.println("<br/>");
        try {
            mh = new MusikkHandler(" ", " ", " ", " ");
            for (Album a : mh.getRows(genre))
                out.println("<p>" + a + "</p>");
        } catch (SQLException e) {
            e.printStackTrace(out);
        }
        out.println("</body>");
        out.println("</html>");
    }

}

更新：我在浏览器中遇到以下错误堆栈跟踪：

java.sql.SQLException: No suitable driver found for
jdbc:mysql://localhost/pg3100 at
java.sql.DriverManager.getConnection(Unknown Source) at
java.sql.DriverManager.getConnection(Unknown Source) at
db.ConnectToDB.(ConnectToDB.java:10) at
nr3.model.MusikkHandler.(MusikkHandler.java:20) at
nr3.servlets.MusikkValg.doGet(MusikkValg.java:39) at
javax.servlet.http.HttpServlet.service(HttpServlet.java:618) at
javax.servlet.http.HttpServlet.service(HttpServlet.java:725) at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:534)
at
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
at
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
at
org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:277)
at
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2381)
at
org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2370)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)

解决方法:

首先,您必须在开始时注册您的驱动程序,以便DriverManager在获得连接时可以使用它. It might vary就实施了.

DriverManager.registerDriver (new com.mysql.jdbc.Driver());

要么

Class.forName("com.mysql.jdbc.Driver"); 

然后,您可以执行getConnection(),因为您将注册一个DriverManager使用的驱动程序.

第二：/ webapps / ROOT / WEB-INF / lib是一个不同的上下文,除非你设置应用程序as shown in this question的上下文路径,否则它的库将无法用于你的应用程序.如果你想添加它,请尝试放置你的JDBC驱动程序首先在/ webapps /< yourapp> / lib上. Tomcat lib也可以正常工作(但是当你分发应用程序时,它可能与部署在那里的其他应用程序冲突,使用不同版本的驱动程序等)

第三：在这里提问时,尽量将可验证的例子减少到可读的范围.有很多代码与您的问题无关.减少使您更容易阅读您的问题并提供帮助.

标签：mysql,servlets,tomcat8
来源： https://codeday.me/bug/20190623/1271549.html

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