我无法将JDBC连接到我的数据库,出现以下错误
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(); } } }
根据stacktrace的说明,您使用的MySQL Connector / J版本使用的是java.util.regex.MatcherAndroid不支持的功能(可能是named组)。解决方法是使用MySQL Connector / J的5.1.x版本而不是8.0.x版本。
java.util.regex.Matcher
但是,您不应使用Android应用程序中的JDBC。它是不安全的,并且通常无法直接连接到数据库。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。