This example shows how to render Spring view in JSON format. Spring provides MappingJackson2JsonView to achieve that. By default, the entire contents of the model Map (populated in a controller method) will be rendered in JSON (except for the framework-specific objects).
Example
Additional Maven Dependency
pom.xml<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.2</version>
</dependency>
Java Config class
@EnableWebMvc
@Configuration
@ComponentScan
public class MyWebConfig {
@Bean
public ViewResolver beanNameViewResolver() {
BeanNameViewResolver resolver = new BeanNameViewResolver();
return resolver;
}
@Bean("currencyRateView")
public View jsonView() {
MappingJackson2JsonView view = new MappingJackson2JsonView();
return view;
}
@Bean
public ViewResolver jspViewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/views/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
}
In above configuration, we are using BeanNameViewResolver for resolving the JSON view by it's bean name.
Spring Controller
@Controller
@RequestMapping("/")
public class MyController {
@GetMapping("/")
public String mainView() {
return "main";
}
@GetMapping("/rates")
public String handleForexRequest(Model model) {
model.addAttribute("currencyRates", getCurrencyRates());
return "currencyRateView";
}
.............
}
public class CurrencyRate {
private String currencyPair;
private Date date;
private BigDecimal askPrice;
private BigDecimal bidPrice;
.............
}
src/main/webapp/WEB-INF/views/main.jsp<html>
<body>
<h2>Spring JSON view Example</h2>
<a href="/rates">Currency Rates</a>
</body>
</html>
To try examples, run embedded tomcat (configured in pom.xml of example project below):
mvn tomcat7:run-war Output
On clicking the 'Currency Rates' link:
Download JSON view as file
To download JSON as file, we need to set 'Content-Disposition' header in our controller method:
@GetMapping("/rates")
public String handleForexRequest(Model model, HttpServletResponse response) {
response.setHeader("Content-Disposition", "attachment; filename=rates.json");
model.addAttribute("currencyRates", getCurrencyRates());
return "currencyRateView";
}
Example ProjectDependencies and Technologies Used: - spring-webmvc 5.0.1.RELEASE: Spring Web MVC.
- javax.servlet-api 3.1.0 Java Servlet API
- jackson-databind 2.9.2: General data-binding functionality for Jackson: works on core streaming API.
- JDK 1.8
- Maven 3.3.9
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