In a Spring MVC project, we can directly return a JSON object. This feature is very useful when combined with ajax request from the client side. Here is few simple step to do this:
- Import JSON dependencies (jackson library) to your project
- Create Java objects, which will be converted to JSON object
- Create a simple Spring Controller to handle the request
- Test it using jetty server.
You can also download the source code here: https://github.com/nxhoaf/spring-mvc-json. Here, I assume that you are already familiar with Maven. If it’s not the case, you can certainly manually insert dependencies in your classpath.
1. JSON dependencies to your pom.xml
<!-- Enable JSON via Jackson --> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-core-asl</artifactId> <version>1.9.10</version> </dependency> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-mapper-asl</artifactId> <version>1.9.10</version> </dependency>
2. Java Object, which will be converted to JSON
// --------------- Person.java ------------------
package com.gmail.nxhoaf;
public class Person {
private String name;
private int age;
public Person() {}
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
// --------------- Shop.java ------------------
package com.gmail.nxhoaf;
import java.util.ArrayList;
import java.util.List;
public class Shop {
private String name;
private List<Person> staffs;
public Shop() {
staffs = new ArrayList<Person>();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Person> getStaffs() {
return staffs;
}
public void setStaffs(List<Person> staffs) {
this.staffs = staffs;
}
public void addStaff(Person staff) {
staffs.add(staff);
}
}
3. Create simple Spring Controller
package com.gmail.nxhoaf;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
@RequestMapping("/json")
public class JSonController {
@RequestMapping(method = RequestMethod.GET)
public @ResponseBody Shop getShopInJSON() {
Shop shop = new Shop();
shop.setName("myShop");
Person p1 = new Person("Alice", 20);
Person p2 = new Person("Bob", 30);
shop.addStaff(p1);
shop.addStaff(p2);
return shop;
}
}
That is! Now, we test it with our jetty server. You might want to see here Spring MVC: Creating a Project from Scratch using Maven to see how to run a Spring MVC project with jetty
mvn clean install mvn jetty:run
Then, open http://localhost:8080/spring-mvc-json/json, you should see the following result:
