Question

我有一个从教程Point复制的简单JAVA类。我正处于JAVA的学习阶段。

//STEP 1. Import required packages
import java.sql.*;

public class FirstExample {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "oracle.jdbc.driver.OracleDriver";  
static final String DB_URL = "jdbc:oracle:thin:@localhost:1521:XE";

 //  Database credentials
static final String USER = "primedetail";
static final String PASS = "primedetail";

 public static void main(String[] args) {
 Connection conn = null;
 Statement stmt = null;
 try{
  //STEP 2: Register JDBC driver
  Class.forName("oracle.jdbc.driver.OracleDriver");

  //STEP 3: Open a connection
  System.out.println("Connecting to database...");
  conn = DriverManager.getConnection(DB_URL,USER,PASS);

  //STEP 4: Execute a query
  System.out.println("Creating statement...");
  stmt = conn.createStatement();
  String sql;
  sql = "SELECT id, first, last, age FROM Employees";
  ResultSet rs = stmt.executeQuery(sql);

  //STEP 5: Extract data from result set
  while(rs.next()){
     //Retrieve by column name
     int id  = rs.getInt("id");
     int age = rs.getInt("age");
     String first = rs.getString("first");
     String last = rs.getString("last");

     //Display values
     System.out.print("ID: " + id);
     System.out.print(", Age: " + age);
     System.out.print(", First: " + first);
     System.out.println(", Last: " + last);
  }
  //STEP 6: Clean-up environment
  rs.close();
  stmt.close();
  conn.close();
 }catch(SQLException se){
  //Handle errors for JDBC
  se.printStackTrace();
 }catch(Exception e){
  //Handle errors for Class.forName
  e.printStackTrace();
 }finally{
  //finally block used to close resources
  try{
     if(stmt!=null)
        stmt.close();
  }catch(SQLException se2){
  }// nothing we can do
  try{
     if(conn!=null)
        conn.close();
  }catch(SQLException se){
     se.printStackTrace();
    }//end finally try
 }//end try
 System.out.println("Goodbye!");
}//end main
}//end FirstExample

我更改了数据库字符串并从cmd提示符广告记事本

运行了该文件

 C:\SK\Java1\1>javac FirstExample.java

  C:\SK\Java1\1>java FirstExample
  java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at FirstExample.main(FirstExample.java:18)
 Goodbye!

  C:\SK\Java1\1>

我已经尝试过将jaba12.xar复制到类路径C：\ SK \ Java1 \ 1，它没有用完.. 欢迎任何帮助.. 在此先感谢..

Answer 1

也许您可以检查数据库连接？当我实现这个相同的教程时，我在db地址中的端口号之后添加了/username。也许这可能有所作为。

java.lang.ClassNotFoundException：java.net.URLClassLoader.findClass中的oracle.jdbc.driver.OracleDriver（未知来源）

1 个答案: