使用JDBC，Android Studio进行MySQL连接 [英] MySQL connection using jdbc, android studio

问题描述

我是Android Studio的新手，希望您不要觉得我的问题很愚蠢.我试图在android studio的终端中编写一个小程序.当我尝试在终端中运行相同的程序时(我不是在android studio上运行)，它工作正常.我通过以下

//执行后错误

  java.lang.ClassNotFoundException:com.mysql.jdbc.Driver在java.net.URLClassLoader.findClass(URLClassLoader.java:381)在java.lang.ClassLoader.loadClass(ClassLoader.java:424)在sun.misc.Launcher $ AppClassLoader.loadClass(Launcher.java:335)在java.lang.ClassLoader.loadClass(ClassLoader.java:357)在java.lang.Class.forName0(本地方法)在java.lang.Class.forName(Class.java:264)在MySQLConnectionExample.main(MySQLConnectionExample.java:16) 

当我从程序中删除"Class.forName("com.mysql.jdbc.Driver")时，这是我得到的错误

 发生错误.也许用户/密码无效java.sql.SQLException:找不到适合的驱动程序jdbc:mysql://127.0.0.1:3306/demo在java.sql.DriverManager.getConnection(DriverManager.java:689)在java.sql.DriverManager.getConnection(DriverManager.java:247)在MySQLConnectionExample.main(MySQLConnectionExample.java:22) 

解决方案

您无法直接从android设备连接到数据库.建立连接到数据库的API.然后将您的Android应用程序连接到这些API.

检查此答案是否有相同的问题 https://stackoverflow.com/a/12233178/4442067

I'm new to Android Studio and I hope you don't consider my question silly.I am trying to write a small program in the terminal of the android studio.When I try to run the same program in my terminal(not android studio) it's working fine.I added the MySQL-connector.jar file in android studio lib by going through this mysql JDBC driver to the android studio.But it didn't work.Please help me.Thanks in advance.

  //MySQConnectionExample.java
  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.SQLException;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.util.Properties;

  public class MySQLConnectionExample {
      public static void main(String[] args) {

            Connection conn1 = null;
            String result = " ";

            try {
                 Class.forName("com.mysql.jdbc.Driver");
                 String url1 = "jdbc:mysql://127.0.0.1:3306/demo";
                 String user = "root";
                 String password = "mypassword";

                 conn1 = DriverManager.getConnection(url1, user, password);
           if (conn1 != null) {
               System.out.println("Connected to the database test1");
           }
           String sql = " select address from pharmacy";
           PreparedStatement prest = conn1.prepareStatement(sql);
           ResultSet rs = prest.executeQuery();
            while(rs.next()) {
               result = rs.getString(1);
               System.out.println(result);

            }

        } catch (SQLException ex) {
        System.out.println("An error occurred. Maybe user/password is invalid");
        ex.printStackTrace();
    }  catch (ClassNotFoundException e) {
                e.printStackTrace();
    }
  }
}

//Error after execution

    java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at MySQLConnectionExample.main(MySQLConnectionExample.java:16)

When I remove "Class.forName("com.mysql.jdbc.Driver")" from the program this is the error i get

     An error occurred. Maybe user/password is invalid                         
    java.sql.SQLException: No suitable driver found for 
    jdbc:mysql://127.0.0.1:3306/demo
    at java.sql.DriverManager.getConnection(DriverManager.java:689)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at MySQLConnectionExample.main(MySQLConnectionExample.java:22)

解决方案

You can't connect directly to databases from android devices. Build APIs that connects to your database. then connect your Android Application to these APIs.

Check this answer for a the same question https://stackoverflow.com/a/12233178/4442067

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