Flex and background database connection (remoteobject)

After several days of hard work, we can finally connect flex to the back-end database. Using the remoteobject method, the configuration is indeed troublesome. To sum up:

Installation Tool: myeclipse

Flex

Blazeds. War

Mysql-connector-java-5.1.7-bin.jar

Configuration process:

1. Install the flex plug-in myeclipse (reference: http://www.blogjava.net/rainwindboys/archiv/2009/06/24/232914.html)

2. Create a web project in myeclipse

3. Introduce database-driven mysql-connector-java-5.1.7-bin.jar of Java and MySQL in web engineering

In the Java build path libraries in properties, select Add external jars to introduce the package.

4. Right-click the project in the flex view and use add web project capablity to cancel the Create web. xml check box default.

Right-click the project and add Web Support to the flex Project (role: to allow tomcat to load this project, because Tomcat can only load web projects)

5. Change the flex server in properties to the root URL of http: // localhost: 8080.

Context root is/login

Import blazeds. War (Lite version of LCDs) in deploy flex war)

6. Configure webroot-> flex-> Add to remoting-config.xml

<Destination ID = "remotelogin">
<Properties>
<Source> com. Test. login </source>
</Properties>
</Destination>

Com. Test. login is a Java file referenced in the src directory.

In the. mxml file

<Mx: remoteobject id = "firstro" Destination = "remotelogin" result = "getroresult (event)"/>

Then we can call the Java method in the trigger event (firstro) of the button through the above remoteobject component ID (firstro) instance as follows:

Private function firstro (str1: String, str2: string): void {
Firstro. checklogin (str1, str2); // use this method to pass two parameters to the Method

}

7. Summary

Remoteobject background connection method: There are two methods to handle returned events: event listening, directly return

(1) first, we will introduce direct return, which is shown in the following example:

<Mx: remoteobject id = "firstro" Destination = "remotelogin" result = "getroresult (event)"/>

Private function getroresult (E: resultevent): void {
VaR Infos: string;
Infos = E. Result. tostring (); // This is a parameter returned from the method and determined based on the parameter
If (Infos = "login "){

Alert. Show ("login"); // login Processing

} Else {

Alert. Show ("not logged on"); // login process

}

(2) Introduction to the event listening method

<Mx: remoteobject Destination = "remotelogin" id = "remotehello"> </MX: remoteobject>
<Mx: button x = "192" Y = "255" label = "button" Click = "testlogin ()"/>

Public Function testlogin (): void {
VaR lognam: String = username. text;
VaR logpassword: String = userpassword. text;
Remotehello. checklogin (lognam, logpassword );
Remotehello. addeventlistener (resultevent. Result, getrohellores); // In the button event, listen to whether the Java program on the server is completed and return the result.
}

Private function getrohellores (E: resultevent): void {// processing when the returned result is returned
// Alert. Show (E. Result. tostring ());
Show. Visible = "true ";
Show. Text = E. Result. tostring ();

}

8. Problems:

Cache: it is not a big problem. It can be run every time it is modified correctly.

Data Display problem: Alert. Show ("output string") (show cannot be less)

Or use the component output:

<Mx: Label x = "25" Y = "16" text = "" id = "show" fontsize = "15" width = "66"/>

Show. Visible = "true ";
Show. Text = E. Result. tostring ();

9. Example

// Login. mxml

<? XML version = "1.0" encoding = "UTF-8"?>
<Mx: Application xmlns: MX = "http://www.adobe.com/2006/mxml" layout = "absolute">
<Mx: SCRIPT>
<! [CDATA [
Import MX. rpc. Events. resultevent;
Import MX. Controls. Alert;
Import MX. Collections. arraycollection;
Private function firstro (str1: String, str2: string): void {
Firstro. checklogin (str1, str2); // use this method to pass two parameters to the Method

}
Private function getroresult (E: resultevent): void {
VaR Infos: string;
Infos = E. Result. tostring (); // This is a parameter returned from the method and determined based on the parameter
// Show. Visible = "true ";
// Show. Text = E. Result. tostring ();
// Alert. Show (Infos );
// Show. Text = Infos;
If (Infos = "login "){

Alert. Show ("login"); // login Processing

} Else {

Alert. Show ("not logged on"); // login process

}
}
]>
</MX: SCRIPT>
 
<Mx: remoteobject id = "firstro" Destination = "remotelogin" result = "getroresult (event)"/>
<Mx: canvas x = "148" Y = "157" width = "200" Height = "200" fontsize = "12">
<Mx: Label x = "25" Y = "48" text = "user"/>
<Mx: Label x = "25" Y = "86" text = "passwd"/>
<Mx: textinput x = "81" Y = "46" width = "109" id = "name1"/>
<Mx: textinput x = "81" Y = "84" width = "109" id = "passwd" displayaspassword = "true"/>
<Mx: button x = "25" Y = "142" label = "login" Click = "firstro (name1.text. tostring

(), Passwd. Text. tostring () "/>
<Mx: button x = "125" Y = "142" label = "button"/>
<Mx: Label x = "25" Y = "16" text = "" id = "show" fontsize = "15" width = "66"/>

</MX: canvas>
</MX: Application>

// Login. Java

Package com. test;
Import java. SQL. resultset;
Import java. SQL. sqlexception;
Import java. util. arraylist;
Import java. util. List;

Public class login {

Testdao test = new testdao ();
Public String checklogin (string name, string password ){
// System. Out. println (name );
String temp = "not logged on ";
String SQL = "select * From t_user where username = '" + name + "' and

Userpassword = '"+ password + "'";
Resultset rs = test. selectsql (SQL );
Try {
If (Rs. Next ()){
Temp = "login ";

}
} Catch (sqlexception e ){
E. printstacktrace ();
}
// System. Out. println (temp );
Return temp;
}
}

// Testdao. Java

Package com. test;
Import java. SQL. connection;
Import java. SQL. drivermanager;
Import java. SQL. resultset;
Import java. SQL. sqlexception;
Import java. SQL. statement;
Public class testdao {
Private Static string username = "root ";
Private Static string Password = "123456 ";
Private Static string database = "Web ";
Private statement stmt = NULL;
Private resultset rs = NULL;
Private Static connection con = NULL;
Private Static string url = "JDBC: mysql: // localhost: 3306/" + database + "?

Useunicode = true & characterencoding = utf8 ";

Static {
Try {
Class. forname ("com. MySQL. JDBC. Driver"). newinstance ();
Con = drivermanager. getconnection (URL, username, password );
} Catch (exception e ){
E. printstacktrace ();
}
}

Public resultset selectsql (string SQL ){

Try {
Stmt = con. createstatement ();
Rs1_stmt.exe cutequery (SQL );
} Catch (sqlexception e ){
// Todo auto-generated Catch Block
E. printstacktrace ();
}
Return Rs;
}
// Insert Delete update
Public void updatesql (string SQL ){

Try {
Stmt = con. createstatement ();
Stmt.exe cuteupdate (SQL );
} Catch (sqlexception e ){
// Todo auto-generated Catch Block
E. printstacktrace ();
}
}
Public void getclose (){
Try {
If (con! = NULL ){
Con. Close ();
}
If (RS! = NULL ){
Rs. Close ();
}
} Catch (sqlexception e ){
// Todo auto-generated Catch Block
E. printstacktrace ();
}
}
}

// Remoteing-config.xml

<Destination ID = "remotelogin">
<Properties>
<Source> com. Test. login </source>
</Properties>
</Destination>