sing Spring MVC we can send to the client data in JSON format, but what if the client sends POST request with data in JSON format? Here we will see how Spring MVC “auto” maps JSON data sent by client POST request into Java object.
Objectives:
- How client request “GET” data in json format?
- How client send “POST” data in json format using jQuery.ajax()?
- How Spring MVC Controller can map json into java object?
Environment:
- Eclipse
- Maven (optional)
- Browser (Firefox, Chrome or IE)
- Java Server (Jetty, Apache,…)
Libraries:
- Spring Framework
- Jackson
- jQuery
<dependencies> <dependency><!-- spring mvc --> <groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>3.0.5.RELEASE</version> </dependency> <dependency><!-- jackson --> <groupId>org.codehaus.jackson</groupId><artifactId>jackson-mapper-asl</artifactId><version>1.4.2</version> </dependency> </dependencies>
( 1 ) Java Project
( 2 ) Java Code & XML Configuration
- RestController.java
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package
com.hmkcode.controllers;
import
javax.servlet.http.HttpServletResponse;
import
org.springframework.stereotype.Controller;
import
org.springframework.web.bind.annotation.RequestBody;
import
org.springframework.web.bind.annotation.RequestMapping;
import
org.springframework.web.bind.annotation.RequestMethod;
import
org.springframework.web.bind.annotation.ResponseBody;
import
com.hmkcode.vo.Person;
@Controller
@RequestMapping
(
"/cont"
)
public
class
RestController {
public
RestController(){
System.out.println(
"init RestController"
);
}
//this method responses to GET request http://localhost/spring-mvc-json/rest/cont
// return Person object as json
@RequestMapping
(method = RequestMethod.GET)
public
@ResponseBody
Person get(HttpServletResponse res) {
Person person =
new
Person();
person.setId(
1
);
person.setName(
"hmk"
);
return
person;
}
//this method response to POST request http://localhost/spring-mvc-json/rest/cont/person
// receives json data sent by client --> map it to Person object
// return Person object as json
@RequestMapping
(value=
"person"
, method = RequestMethod.POST)
public
@ResponseBody
Person post(
@RequestBody
final
Person person) {
System.out.println(person.getId() +
" "
+ person.getName());
return
person;
}
}
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- Person.java
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package
com.hmkcode.vo;
import
java.io.Serializable;
public
class
Person
implements
Serializable {
private
static
final
long
serialVersionUID = 1L;
private
int
id;
private
String name;
//getters and setters...
}
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- rest-servlet.xml
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<
beans
...>
<
context:component-scan
base-package
=
"com.hmkcode.controllers"
/>
<
mvc:annotation-driven
/>
</
beans
>
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- web.xml
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.......
<
servlet
>
<
servlet-name
>rest</
servlet-name
>
<
servlet-class
>org.springframework.web.servlet.DispatcherServlet</
servlet-class
>
</
servlet
>
<
servlet-mapping
>
<
servlet-name
>rest</
servlet-name
>
<
url-pattern
>/rest/*</
url-pattern
>
</
servlet-mapping
>
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- index.html –> $.ajax()
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<html>
......
<script type=
"text/javascript"
>
$(document).ready(
function
(){
sendAjax();
});
function
sendAjax() {
$.ajax({
url:
"/spring-mvc-json/rest/cont/person"
,
type:
'POST'
,
dataType:
'json'
,
data:
"{\"name\":\"hmkcode\",\"id\":2}"
,
contentType:
'application/json'
,
mimeType:
'application/json'
,
success:
function
(data) {
alert(data.id +
" "
+ data.name);
},
error:
function
(data,status,er) {
alert(
"error: "
+data+
" status: "
+status+
" er:"
+er);
}
});
}
</script>
......
</html>
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( 3 ) Run & Test
- Run Jetty “or your” server
- http://localhost:8080/spring-mvc-json/rest/cont
- Thsi url will call the first method RestController.get() return Person object in json format
- http://localhost:8080/spring-mvc-json/index.html
- This html page contains jQuery.ajax() function that will call the second method RestController.post() on the load of the paeg.
- $.ajax() will send json data data: “{\”name\”:\”hmkcode\”,\”id\”:2}”
- Controller will receive this json data mapp into java object using @RequestBody
- Controller will return data again to the client in json format too.
Soruce Code: @ github