Parcel? cn . hpu . BBS . util；
Import? Java . SQL . connection；
Import? Java . SQL . driver manager；
Import? Java . SQL . prepared statement；
Import? Java . SQL . resultset；
Import? Java . SQL . SQL exception；
Import? Java.sql. statement;
Public? Class? DB？ {
//? Defining database drivers for MySQL
Public? Static electricity Final? String? DBDRIVER？ =? “com.mysql.jdbc.Driver”？ ;
//Define the database connection address of mysql:
Public? Static electricity Final? String? DBDURL？ =? " JDBC:MySQL://localhost/BBS 20 14 "？ ;
The connection user name of //mysql database//
Public? Static electricity Final? String? DBUSER？ =? "Root"? ;
//mysql database connection password
Public? Static electricity Final? String? DBPASS？ =? " 1234"? ;
Public? Static electricity Contact? createConn(){
Contact? Kang En? = null
Try it? {
class . forname(DBDRIVER)；
conn = driver manager . getconnection(db durl，DBUSER，db pass)；
}? Catch? (ClassNotFoundException？ e)？ {
e . printstacktrace()；
}? Catch? (SQLException？ e)？ {
e . printstacktrace()；
}
Return? conn
}
Public? Static electricity A prepared report? Prepare (connect? Control room, string? sql){
A prepared report? ps = null
Try it? {
PS = conn . prepare statement(SQL)；
}? Catch? (SQLException？ e)？ {
//? Todo? Automatically generated? Catch? block
e . printstacktrace()；
}
Return? PS；
}
Public? Static electricity Invalid? Close (connect? Connect) {
if(conn==null)？ Return;
Try it? {
conn . close()；
conn = null
}? Catch? (SQLException？ e)？ {
//? Todo? Automatically generated? Catch? block
e . printstacktrace()；
}
}
Public? Static electricity Invalid? Close (declare? stmt){
if(stmt==null)？ Return;
Try it? {
stmt . close()；
stmt = null
}? Catch? (SQLException？ e)？ {
//? Todo? Automatically generated? Catch? block
e . printstacktrace()；
}
}
Public? Static electricity Invalid? Close (ResultSet? rs){
if(rs==null)？ Return;
Try it? {
RS . close()；
rs = null
}? Catch? (SQLException？ e)？ {
//? Todo? Automatically generated? Catch? block
e . printstacktrace()；
}
}
} a JavaBean belonging to the} category:
Parcel? cn . hpu . BBS . model；
Public? Class? Category? {
Private? int？ id；
Private? String? Name;
Private? String? Description;
Public? int？ getId()？ {
Return? id；
}
Public? Invalid? setId(int？ id)？ {
This. id? =? id；
}
Public? String? getName()？ {
Return? Name;
}
Public? Invalid? SetName (string? Name)? {
This name? =? Name;
}
Public? String? getDescription()？ {
Return? Description;
}
Public? Invalid? SetDescription (string? Description)? {
This. Description? =? Description;
}
} Operation classes for databases and categories://To put it bluntly, it means adding, deleting, querying and repairing.
& ltpre？ name="code "？ Class = "java"> package? cn . hpu . BBS . service；
Import? Java . SQL . connection；
Import? Java . SQL . prepared statement；
Import? Java . SQL . resultset；
Import? Java . SQL . SQL exception；
Import? Java . util . ArrayList；
Import? Java . util . list；
Import? cn . hpu . BBS . model . category；
Import? cn . hpu . BBS . util . db；
Public? Class? CategoryService？ {
Public? Invalid? Add (category? c){
Contact? conn = db . create conn()；
String? sql="insert？ Become? Category? (name, description)? Values? (? ,? )";
A prepared report? ps=DB.prepare(conn，SQL)；
Try it? {
ps.setString( 1，？ c . getname())；
ps.setString(2，？ c . get description())；
PS . execute update()；
}? Catch? (SQLException？ e)？ {
e . printstacktrace()；
}
db . close(PS)；
DB.close (connection);
}
Public? List & lt category & gt? list(){
Contact? conn = db . create conn()；
String? sql="select？ *? From where? Category ";
A prepared report? ps=DB.prepare(conn，SQL)；
List & lt category & gt? Category = New? ArrayList & lt category & gt ();
Try it? {
Result set? RS = PS . execute query()；
Category? C = empty;
while(rs.next()){
C = new? Category ();
c . setid(RS . getint(" id "))；
c . setname(RS . getstring(" name "))；
c . set description(RS . getstring(" description "))；
categories . add(c)；
}
}? Catch? (SQLException？ e)？ {
e . printstacktrace()；
}
db . close(PS)；
DB.close (connection);
Return? Category;
}
Public? Invalid? Delete (category? c){
delete byid(c . getid())；
}
Public? Invalid? deleteById(int？ id){
Contact? conn = db . create conn()；
String? Sql= "Delete? From where? Category? Where is it? id=？ ”；
A prepared report? ps=DB.prepare(conn，SQL)；
Try it? {
ps.setInt( 1，？ id)；
PS . execute update()；
}? Catch? (SQLException？ e)？ {
e . printstacktrace()；
}
db . close(PS)；
DB.close (connection);
}
Public? Invalid? Update (category? c){
Contact? conn = db . create conn()；
String? Sql= "Update? Category? Settings? Name? =? ,? Description? =? Where is it? id？ =";
A prepared report? ps=DB.prepare(conn，SQL)；
Try it? {
ps.setString( 1，？ c . getname())；
ps.setString(2，？ c . get description())；
ps.setInt(3，？ c . getid())；
PS . execute update()；
}? Catch? (SQLException？ e)？ {
e . printstacktrace()；
}
db . close(PS)；
DB.close (connection);
}
Public? Category? loadById(int？ id){
Contact? conn = db . create conn()；
String? sql="select？ *? From where? Category? Where is it? id=？ ”；
A prepared report? ps=DB.prepare(conn，SQL)；
Category? C = empty;
Try it? {
ps.setInt( 1，？ id)；
Result set? RS = PS . execute query()；
if(rs.next()){
C = new? Category ();
c . setid(RS . getint(" id "))；
c . setname(RS . getstring(" name "))；
c . set description(RS . getstring(" description "))；
}
}? Catch? (SQLException？ e)？ {
e . printstacktrace()；
}
db . close(PS)；
DB.close (connection);
Return? c；
}
}