Java Learning (14): JDBC Mode Connection Database Example

Java defines a standard interface and class for JDBC, which provides a uniform way for programmers to manipulate databases.

Download the jar package for the corresponding database and add it to the project.

JDBC operates in a single way, consisting of five processes:

1. Register the database driver with the JDBC Class library provided by the database vendor to the DriverManager

2. Connect to the database using the Getconnection () method provided by the DriverManager

3. Establishing an SQL statement object through the Createstatement method of the Connection object of the database

4. Execute the SQL statement and return the result collection to ResultSet

5. Using the while loop to read the results

6. Closing Database Resources

Code examples

1 Importjava.sql.Connection;2 ImportJava.sql.DriverManager;3 ImportJava.sql.ResultSet;4 Importjava.sql.SQLException;5 Importjava.sql.Statement;6 7  Public classTestjdbc8 {9     Private Final StaticString url = "Jdbc:mysql://localhost:3306/test";Ten      One     Private Final StaticString user = ""; A      -     Private Final StaticString Password = ""; -      the      Public Static voidMain (string[] args) -     { -ResultSet rs =NULL; -Statement stmt =NULL; +          -         //JDBC Driver loading + Driverloader (); A         //Get database connection atConnection conn =connectionget (); -         Try -         { -stmt =conn.createstatement (); -String sql = "SELECT * FROM LJF"; -rs =stmt.executequery (SQL); in              while(Rs.next ()) -             { toSystem.out.print (Rs.getint ("id") + ""); +System.out.print (rs.getstring ("name") + ""); -             } the         } *         Catch(SQLException e) $         {Panax NotoginsengSYSTEM.OUT.PRINTLN ("Data manipulation error"); - e.printstacktrace (); the         } +         finally A         { the             //Close the database + Close (RS, stmt, conn); -         } $     } $      -     Private Static voidDriverloader () -     { the         Try -         {WuyiClass.forName ("Com.mysql.jdbc.Driver");//load MySQL driver the         } -         Catch(classnotfoundexception e) Wu         { -SYSTEM.OUT.PRINTLN ("Driver load Error"); About e.printstacktrace (); $         } -     } -      -     Private StaticConnection connectionget () A     { +Connection conn =NULL; the         Try -         { $conn =drivermanager.getconnection (URL, user, password); the         } the         Catch(SQLException e) the         { theSYSTEM.OUT.PRINTLN ("Database link Error"); - e.printstacktrace (); in         } the         returnConn; the     } About      the     Private Static voidClose (ResultSet rs, Statement stmt, Connection conn) the     { the         Try +         { -             if(rs! =NULL) the             {Bayi rs.close (); thers =NULL; the             } -             if(stmt! =NULL) -             { the stmt.close (); thestmt =NULL; the             } the             if(Conn! =NULL) -             { the conn.close (); theconn =NULL; the             }94         } the         Catch(Exception e) the         { theSYSTEM.OUT.PRINTLN ("Database shutdown error");98 e.printstacktrace (); About         } -     }101}

Java Learning (14): JDBC Mode Connection Database Example