Question

我写了以下代码。在步骤5执行“显示记录”后，它会抛出一个耗尽的ResultSet错误。我已阅读了几个问题但没有一个处理类似的问题。由于显而易见的原因，我用星号替换了用户名和密码

 package org.oracle.pojo;
//STEP 1. Import required packages
import java.sql.*;

 public class JDBCExample {


// JDBC driver name and database URL
   static final String JDBC_DRIVER = "oracle.jdbc.driver.OracleDriver";  
   static final String DB_URL = "jdbc:oracle:thin:@10.180.35.58:1521:DBV6SP1M";

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

public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   ResultSet rs = null;
   try{
      //STEP 2: Register JDBC driver
      Class.forName(JDBC_DRIVER);
  //STEP 3: Open a connection
  System.out.println("Connecting to database...");
  conn = DriverManager.getConnection(DB_URL,USER,PASS);

  //STEP 4: Execute a query to create statment with
  // required arguments for RS example.
  System.out.println("Creating statement...");
  stmt = conn.createStatement(
                       ResultSet.TYPE_SCROLL_INSENSITIVE,
                       ResultSet.CONCUR_READ_ONLY);
  String sql;
  sql = "SELECT id, first, last, age FROM Employees";

  boolean status = stmt.execute(sql);
  if(status){
      //query is a select query.
      rs = stmt.getResultSet();
 }


  // Move cursor to the last row.
  System.out.println("Moving cursor to the last...");
  rs.last();


  //-------------------------------------------------------------------------
  //STEP 5: Extract data from result set
  System.out.println("Displaying record...");
  //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);

  // Move cursor to the first row.
  System.out.println("Moving cursor to the first row...");
  rs.first();

  //STEP 6: Extract data from result set
  System.out.println("Displaying record...");
  //Retrieve by column name
  id  = rs.getInt("id");
  age = rs.getInt("age");
  first = rs.getString("first");
  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);
 // Move cursor to the first row.

  System.out.println("Moving cursor to the next row...");
  rs.next();

  //STEP 7: Extract data from result set
  System.out.println("Displaying record...");

  id  = rs.getInt("id");
  age = rs.getInt("age");
  first = rs.getString("first");
  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 8: 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 JDBCExample

Answer 1

如果你的表中只有一行，则第一行和最后一行是相同的，而next（）将是你表的behind the end行。

在处理ResultSet之前，总是查看first（），last（），next（）的返回值

用尽的结果集错误：导出值时出现问题

1 个答案: