Android + MySQL使用com.mysql.jdbc.Driver

Question

我正在编写一个将连接到MySQL服务器的Android应用程序.现在,我正在使用http:// localhost:3306 /通过XAMPP在我的计算机上测试MySQL服务器.以下代码严格地作为JAVA应用程序进行测试时可以正常工作.

import java.sql.*;

public class MySQL{
  public static void main(String[] args) {
    System.out.println("MySQL Connect Example.");
    Connection conn = null;
    String url = "jdbc:mysql://localhost:3306/";
    String dbName = "database";
    String driver = "com.mysql.jdbc.Driver";
    String userName = "root"; 
    String password = "";
    try {
      Class.forName(driver).newInstance();
      conn = DriverManager.getConnection(url+dbName,userName,password);
      System.out.println("Connected to the database");
      conn.close();
      System.out.println("Disconnected from database");
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

但是当我将它添加到我的Android应用程序时,我得到了Exception e错误.

// interact with MySQL!!!
 private View.OnClickListener onSendRequest = new View.OnClickListener() {
  @Override
  public void onClick(View v) {
   EditText username = (EditText) findViewById(R.id.Huusername);
      //    String un = " " + username.getText().toString() + " ";

      System.out.println("MySQL Connect Example.");
      Connection conn = null;
      String url = "jdbc:mysql://localhost:3306/";
      String dbName = "database";
      String driver = "com.mysql.jdbc.Driver";
      String userName = "root"; 
      String password = "";
      try {
        Class.forName(driver).newInstance();
        conn = DriverManager.getConnection(url+dbName,userName,password);
        Toast.makeText(getBaseContext(),
      "Connected to the database.", Toast.LENGTH_LONG)
      .show();
        conn.close();
        Toast.makeText(getBaseContext(),
      "Disconnected form the database.", Toast.LENGTH_LONG)
      .show();
      } catch (Exception e) {
       Toast.makeText(getBaseContext(),
      "Exception e.", Toast.LENGTH_LONG)
      .show();
        e.printStackTrace();
      }


  }
 };

当我编译我的Android应用程序时,我在控制台中注意到以下语句:

[2011-01-26 16:05:54 - hookup]: Dxwarning: Ignoring InnerClasses attribute for an anonymous inner class
(com.mysql.jdbc.interceptors.ResultSetScannerInterceptor$1) that doesn't come with an
associated EnclosingMethod attribute. This class was probably produced by a
compiler that did not target the modern .class file format. The recommended
solution is to recompile the class from source, using an up-to-date compiler
and without specifying any "-target" type options. The consequence of ignoring
this warning is that reflective operations on this class will incorrectly
indicate that it is *not* an inner class.

我认为这个陈述与我得到的例外有关.有没有人使用MySQL和Android可以引导我朝着正确的方向发展？谢谢

Answer 1

使用JDBC连接器mysql-connector-java-3.0.17-ga-bin.jar,现在是唯一有效的连接器.

检查你的代码,你需要为你的应用程序的每个活动实现一个连接池,只需添加一个私有的"连接"var并在你的OnCreate方法中初始化,如con = DriveManager.getConnection ......然后使用它每次需要访问MYSQL时都会使用private var.