Java groovlets and common web Project Integration

Because of the convenience of groovy dynamic language, there are two options to integrate in common web projects.

It is very convenient to use the groovy-based grails framework and is suitable for new projects.

Use groovy integration to maintain existing projects (after all, upgrading a project according to grails requires a lot of work for large projects)

The following describes how to maintain and use groovy for a project:

Web. xmlConfiguration: Add groovyResponse Servlet

<Servlet>

<Servlet-Name> groovy </servlet-Name>

<Servlet-class> groovy. servlet. policyservlet </servlet-class>

</Servlet>

<Servlet-mapping>

<Servlet-Name> groovy </servlet-Name>

<URL-pattern> *. Groovy </url-pattern>

</Servlet-mapping>

Add dependency Library

All dependencies for groovy-all-1.7.10.jar groovy

Mysql-connector-java-5.0.7-bin.jar: MySQL driver, database project use

Example

The following are simple instances that use SQL and data binding.

Importgroovy. SQL. SQL

If (! Session)

{

Session = request. getsession (true)

}

If (! Session. Counter)

{

Session. Counter = 1

}

/* Drop table if exists 'Demo'. 'text _ search ';

Create Table 'Demo'. 'text _ search '(

'Id' bigint (20) not null auto_increment,

'Version' bigint (20) not null,

'Description' varchar (255) not null,

'Username' varchar (255) not null,

Primary Key ('id '),

Unique key 'username' ('username ')

) Engine = MyISAM auto_increment = 4 default charset = Latin1;

*/

Defdb = groovy. SQL. SQL. newinstance ('jdbc: mysql: // localhost: 3306/demo', 'root', '', 'com. mySQL. JDBC. driver ')

Def name = Params. Guess

Defdesc = "descdd"

Try

{

Db.exe cute ("insert into text_search (version, username, description) values (1, $ {name}, $ {DESC })")

} Catch (exception)

{

Println 'already exists'

}

Html.html {

Head {

Title ("groovy Demo ")

}

Body {

P ("$ {request. remotehost }::: {session. Counter }")

H1 'variables in the binding :'

Table (Summary: 'binding '){

Tbody {

Binding. variables. Each {key, value->

Tr {

Tdkey. tostring ()

TD (value? Value. tostring (): 'null ')

}

}

}

}

HR ()

DB. eachrow ("select * From text_search "){

Println it. ID

Printlnit. Username

HR ()

}

}

}

Session. Counter = session. Counter + 1

Use http: // localhost: 8084/demo/Hello. Groovy? Guess = access by demo to write data and read content

For more information, see

Name	Remarks (corresponding in servlet)	Instance usage
Headers	Map type HTTP request headers	Headers. Host
Params	Map type HTTP Request Parameters	Params. myparam
Session	Servletsession, can be null	Session ?. Myparam
Request	Httpservletrequest	Request. remotehost
Response	Httpservletresponse	Response. contenttype = 'text/xml'
Context	Servletcontext	Context. myparam
Application	Servletcontext (same as context)	Application. myparam
Out	Response. Writer	Delayed initialization. It is initialized when it is used for the first time.
Sout	Response. outputstream	Delayed initialization. It is initialized when it is used for the first time.
Html	Builderinitialized as new markupbuilder (out)	Delayed initialization. It is initialized when it is used for the first time.

 

Templatinggroovlets

If you want to process more service pages, you can use templates. For more information, see.

Summary

Not very familiar with Java (such.. Net personnel) maintain existing Java Web projects, and use groovy to quickly follow up. At the same time, due to the simplicity and integration of groovy syntax, for common XML file processing, data processing, and so on, you can use less conciseCodeImplementation

Groovy sample is more systematic and easy to find

And existing Java code can call each other