Question

我正在构建一个基本应用程序，让我扫描RFID标签并将数据推送到SQL服务器。我终于把NFC部分搞砸了（第一个Java / Android应用程序），但我遇到了数据库问题。我已经做了很多搜索，但找不到答案。我知道直接连接到服务器存在安全风险和不良做法，但此应用程序仅安装在一部手机上，仅用于演示/测试目的。任何实际部署都会获得一个Web界面，但现在根本不是一个选项。

我正在使用jtds 1.3.0驱动程序，以及以下代码片段：

    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.Statement;

    import net.sourceforge.jtds.jdbc.*;

    public void query2()
    {
    Log.i("Android"," MySQL Connect Example.");
    Connection conn = null;
    try {
    String driver = "net.sourceforge.jtds.jdbc.Driver";
    Class.forName(driver).newInstance();
    //test = com.microsoft.sqlserver.jdbc.SQLServerDriver.class;
    String connString = "jdbc:jtds:sqlserver://server_ip_address               
    :1433/DBNAME;encrypt=fasle;user=xxxxxxxxx;password=xxxxxxxx;instance=SQLEXPRESS;";
    String username = "xxxxxx";
    String password = "xxxxxxxxxx";
    conn = DriverManager.getConnection(connString,username,password);
    Log.w("Connection","open");
    Statement stmt = conn.createStatement();
    ResultSet reset = stmt.executeQuery("select * from TableName");

    //Print the data to the console
    while(reset.next()){
    Log.w("Data:",reset.getString(3));
    //              Log.w("Data",reset.getString(2));
    }
    conn.close();

    } catch (Exception e)
    {
    Log.w("Error connection","" + e.getMessage());
    }
    }

目前，我的问题是每当我到达

时

    Class.forname(driver).newInstance();

它直接跳到了捕获块。我不知道为什么。我已逐行排队，但在发生异常时无法找到错误消息，并且不知道为什么会这样。谢谢你们。

编辑：我删除了try / catch块然后执行它并从logcat中分配。不确定它是否有帮助，但这是它给了我的东西：

12-12 05:29:37.369: W/dalvikvm(1242): threadid=1: thread exiting with uncaught exception (group=0x4150a930)
12-12 05:29:37.389: E/AndroidRuntime(1242): FATAL EXCEPTION: main
12-12 05:29:37.389: E/AndroidRuntime(1242): java.lang.IllegalStateException: Could not execute method of the activity
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.view.View$1.onClick(View.java:3597)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.view.View.performClick(View.java:4202)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.view.View$PerformClick.run(View.java:17340)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.os.Handler.handleCallback(Handler.java:725)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.os.Handler.dispatchMessage(Handler.java:92)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.os.Looper.loop(Looper.java:137)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.app.ActivityThread.main(ActivityThread.java:5039)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.reflect.Method.invokeNative(Native Method)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.reflect.Method.invoke(Method.java:511)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at dalvik.system.NativeStart.main(Native Method)
12-12 05:29:37.389: E/AndroidRuntime(1242): Caused by: java.lang.reflect.InvocationTargetException
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.reflect.Method.invokeNative(Native Method)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.reflect.Method.invoke(Method.java:511)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at android.view.View$1.onClick(View.java:3592)
12-12 05:29:37.389: E/AndroidRuntime(1242):     ... 11 more
12-12 05:29:37.389: E/AndroidRuntime(1242): Caused by: java.lang.ClassNotFoundException: net.sourceforge.jtds.jdbc.Driver
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.Class.classForName(Native Method)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.Class.forName(Class.java:217)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.Class.forName(Class.java:172)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at com.nateapp.finalproject.MainActivity.sendData(MainActivity.java:261)
12-12 05:29:37.389: E/AndroidRuntime(1242):     ... 14 more
12-12 05:29:37.389: E/AndroidRuntime(1242): Caused by: java.lang.NoClassDefFoundError: net/sourceforge/jtds/jdbc/Driver
12-12 05:29:37.389: E/AndroidRuntime(1242):     ... 18 more
12-12 05:29:37.389: E/AndroidRuntime(1242): Caused by: java.lang.ClassNotFoundException: Didn't find class "net.sourceforge.jtds.jdbc.Driver" on path: /data/app/com.nateapp.finalproject-1.apk
12-12 05:29:37.389: E/AndroidRuntime(1242):     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
12-12 05:29:37.389: E/AndroidRuntime(1242):     at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
12-12 05:29:37.389: E/AndroidRuntime(1242):     ... 18 more

Answer 1

经过一番搜索，有人建议这是1.3.0版本中的一个错误。我只是从我的项目（libs文件夹）中删除了1.3.0版本并删除了1.2.7版本，现在工作正常。

直接在Android中访问SQL数据库

1 个答案: