Java Chapter 27th JDBC

JDBC templates

try {

Class.forName (JDBC driver Class);

1. Load the JDBC Driver

Class. forname ("Com.mysql.jdbc.Driver");

2. Establish a connection with the database

Connection con=drivermanager.getconnection (URL, database user name, password);

URLs are used to identify the database

PreparedStatement Pstmt=con. PreparedStatement ("Query SQL statement");

ResultSet Rs=pstmt.executequery ();

Executes the SQL statement and gets the result returned

while (Rs.next ()) {

int X=rs.getint ("a");

String s=rs.getstring ("B");

Float f=rs.getfloat ("C");

Processing the results of a drop back

}

Rs.close ();

Pstmt.close ();

Con.close (); Close connection

Freeing resources

｝

Package com.test;

Import java.sql.Connection;
Import Java.sql.DriverManager;
Import java.sql.PreparedStatement;
Import Java.sql.ResultSet;
Import java.sql.SQLException;
Import Java.util.Scanner;


public class Test1 {


/**
* @param args
*/
public static void Main (string[] args) {
Connection Conn=null;
PreparedStatement Pstmt=null;
ResultSet Rst=null;

try {
1. Load Driver
Class.forName ("Com.mysql.jdbc.Driver");
2. Establish the connection
Conn=drivermanager.getconnection ("Jdbc:mysql://localhost:3306/nyschool? Characterencoding=utf-8 "," root "," root ");
SYSTEM.OUT.PRINTLN ("Build connection succeeded!! ");
3. Create the Preparestatement interface and compile the SQL statement
Pstmt=conn.preparestatement ("SELECT * from student");
Perform the Delete
Scanner input=new Scanner (system.in);
System.out.print ("Please enter the student number to be deleted:");
int Stuno=input.nextint ();
Two methods:
Method 1:string sql= "DELETE from student WHERE stuno=" +stuno;
Method 2:string sql= "DELETE from student WHERE stuno=7";

Perform the Add
System.out.print ("Please enter the number of learners added:");
int Stuno=input.nextint ();
System.out.print ("Please enter the gender of the participant added:");
String Name=input.next ();
System.out.print ("Please enter the address added:");
String Phone=input.next ();
//
String sql= "INSERT into student VALUES (?, ' a2323 ', ' QQ ',?, 1,?, ' Jiangxi Nanchang ', sysdate (), ' qq.com ')";
Pstmt=conn.preparestatement (SQL); Pre-compilation method
Assign a value to a placeholder
Pstmt.setint (1, Stuno);
Pstmt.setstring (2, name);
Pstmt.setstring (3, phone);
System.out.print ("sql:" +sql);
4. Execute the SQL statement and get the return result
Rst=pstmt.executequery (); Execute Query
int num=pstmt.executeupdate (); Perform additions, deletions and changes
5. Processing return results
if (num>0) {
System.out.println ("\ n Add success! ");
}else{
System.out.println ("\ n Add failed! ");
}

while (Rs.next ()) {

int X=rs.getint ("a");

String s=rs.getstring ("B");

Float f=rs.getfloat ("C");

Processing the results of a drop back

} catch (ClassNotFoundException e) {
TODO auto-generated Catch block
E.printstacktrace ();
}catch (SQLException e) {
TODO auto-generated Catch block
E.printstacktrace ();

}

Java Chapter 27th JDBC