以前工作的時候由於Oracle8i數據庫經常出現用戶過多的錯誤,由於數據量大,經常出現ORA:12500錯誤,但主要原因是訪問過多而引起的,後來就用Java寫了個簡單的用JDBC連接來測試Oracle最大連接數的程序.現在常用MySQL,所以又寫了一個簡單的測試其最大連接數的程序,在此介紹給大家:
import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.sql.ResultSet; import java.sql.SQLException; import Java.io.IOException; class testMaxConn{ public static void main(String args[]){ int count=0; Connection []conn=new Connection[1000]; Statement []stmt =new Statement[1000]; ResultSet []rs =new ResultSet[1000]; try{ Class.forName ("com.MySQL.jdbc.Driver").newInstance(); for(count=0;count<300;count++){ conn[count] = DriverManager.getConnection ("jdbc:mysql://localhost/MySQL", "root", ""); stmt[count]=conn[count].createStatement(); rs[count]=stmt[count].executeQuery ("SELECT * FROM user"); while (rs[count].next()){ //System.out.println(rs.getString(1)+ "\t "+rs.getString(2)); } System.out.print(count+"\t"); } }catch(SQLException ex1){ System.out.println("\n"+ex1.toString()); }catch(InstantiationException ex2){ System.out.println("\n"+ex2.toString()); }catch(ClassNotFoundException ex3){ System.out.println("\n"+ex3.toString()); }catch(IllegalAccessException ex4){ System.out.println("\n"+ex4.toString()); }finally{ try{ System.out.println("\nSystem has opened "+count--+" MySQL connections.\nPress Enter key to close the connections"); System.in.read(); System.out.println ("\nClose the Connections:"); for(;count>=0;count--){ rs[count].close(); stmt[count].close(); conn[count].close(); System.out.print(count+"\t"); } }catch(SQLException ex){ System.out.println ("\n Close connection exception:"+ex.toString()); }catch(IOException io_ex){} }//end the first "try" } }