求救:jdbc连接oracle出现空指针异常
jdbc连接oracle时提示出现空指针异常,为什么呢》?多谢
连的是本地机器
详细:
package day614;
import java.sql.*;
import day614.JdbcUtil;
public class TestConnection {
public static void main(String[] args) throws SQLException {
Connection con=null;
Statement stmt=null;
ResultSet rs=null;
JdbcUtil.getConnection();
stmt=con.createStatement();
String sql="create table test(name varchar2,mark char)";
stmt.executeUpdate(sql);
JdbcUtil.release(rs, stmt, con);
}
}
package day614;
import java.sql.*;
public class JdbcUtil {
static{
String d="oracle.jdbc.driver.OracleDriver";
try {
Class.forName(d);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public static Connection getConnection(){
String url="jdbc:oracle:thin:@127.0.0.1:1521:snowbaby";
String username="system";
String password="system";
Connection con=null;
try{
con=DriverManager.getConnection(url,username,password);
}catch(Exception e){
e.printStackTrace();
}
return con;
}
public static void release(ResultSet rs,Statement stmt,Connection con){
if(rs!=null){
try{
rs.close();
}catch(Exception e){
e.printStackTrace();
}
}
if(stmt!=null){
try{
stmt.close();
}catch(Exception e){
e.printStackTrace();
}
}
if(con!=null){
try{
con.close();
}catch(Exception e){
e.printStackTrace();
}
}
}
public static void release(Object o){
try{
if(o instanceof ResultSet){
((ResultSet)o).close();
}else if(o instanceof Statement){
((Statement)o).close();
}else if(o instanceof Connection){
((Connection)o).close();
}
}catch(Exception e){
e.printStackTrace();
}
}
}
错误信息:
Exception in thread "main" java.lang.NullPointerException
at day614.TestConnection.main(TestConnection.java:12)