sql exception:java.lang.NullPointerException
package function;
//JDBC中的所有类和接口都在java.sql包下。
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class Execute{
private static String driver="oracle.jdbc.OracleDriver";//声明驱动类字符串
//声明数据库连接字符串
private static String url="jdbc:oracle:thin:@localhost:1521:orcl";
private static Connection con=null;//声明数据库连接对象引用
private static Statement stat=null;//声明语句对象引用
//private static PreparedStatement psInsert=null;//声明预编译语句对象引用
static ResultSet rs=null;//声明结果集对象引用
public static Connection getConnection()//得到数据库连接的方法
{
try {
Class.forName(driver);//加载驱动类
con=DriverManager.getConnection(url,"system","abcA1234");//得到连 接
return con;
}
catch (SQLException e) {
e.printStackTrace();
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
finally {
if (con != null) {
try {con.close();
}
catch (SQLException e) {
e.printStackTrace();
}
}
}
return null;
}
public static boolean executeSQL(String sqlString) {
boolean executeFlag;
try {
stat.execute(sqlString);
executeFlag = true;
} catch (SQLException e) {
executeFlag = false;
System.out.println("sql exception:" + e.getMessage());
}
return executeFlag;
}
public static boolean query(String sqlString) {
try {
rs = null;
//System.out.println(sqlString);
rs = stat.executeQuery(sqlString);
} catch (Exception Ex) {
System.out.println("sql exception:" + Ex);
return false;
}
return true;
}
public static void main(String[] args) {
Connection conn = getConnection();
if (conn != null) {
System.out.println("连接成功");
}
else {
System.out.println("连接失败");
}
}
}
