Newbie on the road, lane for nearly half a day, it is can not find out where is the problem, ask bosses save QWQ

My development environment is:

8.0.11 version of mysql database
Driver: mysql connector - Java - 8.0.11. Jar
Android stdio 3.2


Running, the console has been submitted to the following error:



The directory structure is like this:




In the MainActivity code:

 package com. Example. Database_test; 

The import android. OS. Bundle; 
import android.support.v7.app.AppCompatActivity; 
The import android. View. The view; 
The import android. Widget. The Button; 

Public class MainActivity extends AppCompatActivity implements the View. An OnClickListener {

@ Override 
Protected void onCreate (Bundle savedInstanceState) {
Super. OnCreate (savedInstanceState); 
The setContentView (R.l ayout. Activity_main); 

The Button oBtn=(Button) the findViewById (R.i db utton_start); 
OBtn. SetOnClickListener (this); 

} 

@ Override 
Public void onClick (View v) {
The switch (v.g etId ()) {
Case R.i db utton_start: 
New Thread (new Runnable () {
@ Override 
Public void the run () {
Try {
DaoTest. Gets (); 
} the catch (Exception e) {
e.printStackTrace(); 
} 
} 
}). The start (); 
break; 
Default: 
break; 
} 
} 
} 

DaoTest within code:

 package com. Example. Database_test; 


The import android. Util. Log; 

import java.sql.Connection; 
import java.sql.DriverManager; 
Import the Java. SQL. The ResultSet; 
Import the Java. SQL. SQLException; 
Import Java, SQL Statement; 

Public class DaoTest {

Public static void gets () throws SQLException, ClassNotFoundException, InstantiationException, IllegalAccessException {
String driver="com.mysql.cj.jdbc.Driver"; 
The String url="JDBC: mysql://localhost: 3306/day14"; 
String username="XXX"; 
String password="yyy"; 


//1: load the driver 
Class.forname (driver). NewInstance (); 


//2: getting connection 
The Connection conn=DriverManager. GetConnection (url, username, password); 



if(! Conn. IsClosed ()) 
System. Out.println (" succeeded to connect the database!" ); 

//3: access to database SQL statement object 
The Statement st=conn. CreateStatement (); 

//4: SQL statements to the database method, obtain the data is encapsulated into a result set (ResultSet) 
The ResultSet rs=st. executeQuery (" select * from the users "); 

//5: from the result set object, to get the data 
While (rs), next ()) {
The d (" id=", (String) rs. GetObject (" id ")); 
The d (" name=", (String) rs. GetObject (" name ")); 
The d (" password=", (String) rs. GetObject (" password ")); 
The d (" email=", (String) rs. GetObject (" email ")); 
The d (" birthday=", (String) rs. GetObject (" birthday ")); 
} 


//6: release links, and other resources 
rs.close(); 
St. close (); 
Conn. Close (); 

} 

} 

In the MainFest, has set a network access for




The couple is really can't find where the problem, who save QWQ genuflect is begged

CodePudding user response:

Supplement:

Build within the app. Grade is like this:

CodePudding user response:

From the top, bosses help QWQ

CodePudding user response:

? JDBC precompiled add and delete

http://www.verejava.com/? Id=1715771977132

CodePudding user response:

Do not use the root login users

CodePudding user response:

The first time I saw the app directly connect to the database, the server, please do eat

CodePudding user response:

Mysql was installed above your cell phone?
Pay attention to the connection address you,

CodePudding user response:

Your CLass. Class.forname perhaps didn't perform successfully, it will not mistake to quote you empty file address?

CodePudding user response:

So long posts was also interpret