Android上带有DriverManager.getConnection()的UnsupportedOperationException [英] UnsupportedOperationException with DriverManager.getConnection() on Android

问题描述

我无法将JDBC连接到我的数据库，出现以下错误

I am unable to connect JDBC to my database, getting following error

Error :  E/AndroidRuntime: FATAL EXCEPTION: main
 Process: com.example.myprojectapplication, PID: 32686
 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myprojectapplication/com.example.myprojectapplication.MainActivity}:
 java.lang.UnsupportedOperationException
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
     at android.app.ActivityThread.-wrap12(ActivityThread.java)
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
     at android.os.Handler.dispatchMessage(Handler.java:102)
     at android.os.Looper.loop(Looper.java:154)
     at android.app.ActivityThread.main(ActivityThread.java:6077)
     at java.lang.reflect.Method.invoke(Native Method)
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
 Caused by: java.lang.UnsupportedOperationException
     at java.util.regex.Matcher.group(Matcher.java:383)
     at com.mysql.cj.conf.ConnectionUrlParser.isConnectionStringSupported(ConnectionUrlParser.java:152)
     at com.mysql.cj.conf.ConnectionUrl.acceptsUrl(ConnectionUrl.java:258)
     at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:187)
     at java.sql.DriverManager.getConnection(DriverManager.java:569)
     at java.sql.DriverManager.getConnection(DriverManager.java:219)
     at com.example.myprojectapplication.ObjectClass.JDBC.CONN(JDBC.java:19)
     at com.example.myprojectapplication.MainActivity.onCreate(MainActivity.java:72)
     at android.app.Activity.performCreate(Activity.java:6662)
     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
     at android.app.ActivityThread.-wrap12(ActivityThread.java) 
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
     at android.os.Handler.dispatchMessage(Handler.java:102) 
     at android.os.Looper.loop(Looper.java:154) 
     at android.app.ActivityThread.main(ActivityThread.java:6077) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

package com.example.myprojectapplication.ObjectClass;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;


public class JDBC {

    public void CONN() {
        Connection con = null;

        try {
            String url = "jdbc:mysql://localhost:3306/prog";
            String username = "root";
            String password = "mysql";

            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection(url, username, password);

            if (con != null) {
                System.out
                        .println("Successfully connected to MySQL database test");
            }

        } catch (SQLException ex) {
            System.out
                    .println("An error occurred while connecting MySQL databse");
            ex.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedOperationException exa){
            exa.printStackTrace();
        }

    }
}

推荐答案

根据stacktrace，您使用的MySQL Connector/J版本使用的是Android不支持的java.util.regex.Matcher功能(可能

According to the stacktrace, the MySQL Connector/J version you are using is using a java.util.regex.Matcher feature not supported on Android (probably named groups). The workaround is to use a 5.1.x version of MySQL Connector/J instead of a 8.0.x version.

但是，您不应该使用Android应用程序中的JDBC.它是不安全的，并且通常在直接连接到数据库方面表现不佳.正确的解决方案是编写REST服务(或其他形式的Web服务)以在Android应用程序和数据库之间进行中介.

However, you shouldn't use JDBC from Android applications. It is insecure, and generally badly performing to connect to a database directly. The proper solution is to write a REST service (or other form of webservice) to mediate between your Android application and the database.

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