Jcreator:4.5 Pro开发;mysql-connector-java-5.1.7-bin.jar放在C:\Program Files\Java\jre6\lib\ext中而且在classpath中:.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar;C:\mysql-connector-java-5.1.7\mysql-connector-java-5.1.7-bin.jar;
Mysql:登陆用户root,密码mysql,数据库aspnet,其中的表msg:
程序代码如下:
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class MySqlDemo { public MySqlDemo() {
}
public static void main (String[] args)throws SQLException {
String Url="jdbc:mysql://localhost:3306/msg?user=root&password=mysql";
Connection conn;
Statement ment;
ResultSet set;
try{
Class.forName("com.mysql.jdbc.Driver");
}catch(ClassNotFoundException ex)
{
ex.printStackTrace();
}
conn=DriverManager.getConnection(Url);
ment=conn.createStatement();
set=ment.executeQuery("select * from msg");
try{
while(set.next())
{
String city=set.getString(3);
System.out.println(city);
}
}catch(Exception ex)
{
ex.printStackTrace();
}
编译没有错误;但是一执行就出现下面信息:
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at MySqlDemo.main(MySqlDemo.java:24)
Exception in thread "main" java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/msg?user=root&password=mysql
at java.sql.DriverManager.getConnection(DriverManager.java:602)
at java.sql.DriverManager.getConnection(DriverManager.java:207)
at MySqlDemo.main(MySqlDemo.java:31)
请高手指点
或者给出java连接mysql的具体步骤,有可以执行代码更好。
Mysql:登陆用户root,密码mysql,数据库aspnet,其中的表msg:
程序代码如下:
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class MySqlDemo { public MySqlDemo() {
}
public static void main (String[] args)throws SQLException {
String Url="jdbc:mysql://localhost:3306/msg?user=root&password=mysql";
Connection conn;
Statement ment;
ResultSet set;
try{
Class.forName("com.mysql.jdbc.Driver");
}catch(ClassNotFoundException ex)
{
ex.printStackTrace();
}
conn=DriverManager.getConnection(Url);
ment=conn.createStatement();
set=ment.executeQuery("select * from msg");
try{
while(set.next())
{
String city=set.getString(3);
System.out.println(city);
}
}catch(Exception ex)
{
ex.printStackTrace();
}
编译没有错误;但是一执行就出现下面信息:
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at MySqlDemo.main(MySqlDemo.java:24)
Exception in thread "main" java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/msg?user=root&password=mysql
at java.sql.DriverManager.getConnection(DriverManager.java:602)
at java.sql.DriverManager.getConnection(DriverManager.java:207)
at MySqlDemo.main(MySqlDemo.java:31)
请高手指点
或者给出java连接mysql的具体步骤,有可以执行代码更好。
No suitable driver found for jdbc:mysql://localhost:3306/msg?user=root&password=mysql
public MySqlDemo() { static{
try{
Class.forName("com.mysql.jdbc.Driver");
}catch(ClassNotFoundException ex)
{
ex.printStackTrace();
} }
public static Connection getConnection(){
String url = "jdbc:mysql://localhost:3306/msg";
String usr = "root":
String password = "mysql";
return DriverManager.getConnection(url,usr,password);
}
public static void main (String[] args)throws SQLException {
Connection conn = null;
Statement ment = null;
ResultSet set = null;
try{
conn=getConnection();
ment=conn.createStatement();
set=ment.executeQuery("select * from msg");
while(set.next())
{
String city=set.getString(3);
System.out.println(city);
}
}catch(Exception ex) {
ex.printStackTrace();
} finally{
set.close();
ment.close();
conn.close();
}
Url =“mysql://localhost:3306/aspnet”
conn = DriverManager.getConnection(jdbcUrl, "root", "mysql");
try{
Class.forName("com.mysql.jdbc.Driver");
}catch(ClassNotFoundException ex)
{
ex.printStackTrace();
} }
public static Connection getConnection(){
String url = "jdbc:mysql://localhost:3306/aspnet";
String usr = "root":
String password = "mysql";
return DriverManager.getConnection(url,usr,password);
}
public static void main (String[] args)throws SQLException {
Connection conn = null;
Statement ment = null;
ResultSet set = null;
try{
conn=getConnection();
ment=conn.createStatement();
set=ment.executeQuery("select * from msg");
while(set.next())
{
String city=set.getString(3);
System.out.println(city);
}
}catch(Exception ex) {
ex.printStackTrace();
} finally{
set.close();
ment.close();
conn.close();
}
classpath: C:\mysql-connector-java-5.1.7\mysql-connector-java-5.1.7-bin.jar;
路径太长,识别不了!系统识别不了这么长的文件名,可以改为:c:\mysql\mysqljdbc.jar就行了
还有就是建议LZ把url分开写,写成url,user,password这样好点,以后修改方便点
可以参考1楼的做法!
个人建议LZ试着学会用eclipse开发环境,这样就不需要设置环境变量了,
用IDE更便于单个项目管理
问题可能是你的MySql数据库版本和驱动包mysql-connector-java-5.1.7-bin.jar不一致。
1、数据库与驱动版本不兼容(有时候找不到原因是,就是它了)
2、路径问题 (一般的ClassNotFoundException原因都是找不到文件、没有引入包、或是引用和声明不一致……)
这个jar包 你引入到工程中了吗?
-------------------------是URL的问题了
你的数据库是aspnet 你连接数据库里那个数据库么?