Spring 4 MVC GsonHttpMessageConverter Example with configureMessageConverters()
November 06, 2015
Software Used
We are using following software in our example.1. Java 8
2. Spring 4.1
3. Gradle
4. Eclipse
5. Tomcat 8
Gradle File
To enable GsonHttpMessageConverter, we are using gson-2.4-sources.jar.build.gradle
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'war'
archivesBaseName = 'spring4'
version = '1'
repositories {
mavenCentral()
}
dependencies {
compile 'org.springframework.boot:spring-boot-starter-web:1.2.3.RELEASE'
compile 'com.google.code.gson:gson:2.4'
providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat:1.2.3.RELEASE'
}
JavaConfig: Configure GsonHttpMessageConverter using configureMessageConverters()
AppConfig.java
package com.concretepage.config;
import java.util.List;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.GsonHttpMessageConverter;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
@Configuration
@ComponentScan("com.concretepage")
@EnableWebMvc
public class AppConfig extends WebMvcConfigurerAdapter {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
GsonHttpMessageConverter msgConverter = new GsonHttpMessageConverter();
Gson gson = new GsonBuilder().setPrettyPrinting().create();
msgConverter.setGson(gson);
converters.add(msgConverter);
}
}
configureMessageConverters(): It configures the
HttpMessageConverter. If no converter is added, default list of converters are registered automatically.
GsonHttpMessageConverter: It can read and write JSON using Google Gson library.
Controller and Java Bean
BlogController.java
package com.concretepage.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.concretepage.bean.Writer;
@RestController
public class BlogController {
@Autowired
private Writer writer;
@RequestMapping(value = "/blog")
public List<Writer> getBlog() {
return writer.getWriters();
}
}
Writer.java
package com.concretepage.bean;
import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Service;
@Service
public class Writer {
private String name;
private String location;
public Writer(){}
public Writer(String name, String location) {
this.name = name;
this.location = location;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public List>Writer< getWriters() {
List<Writer> list = new ArrayList<>();
list.add(new Writer("Ram","Ayodhya"));
list.add(new Writer("Krishna","Mathura"));
list.add(new Writer("Shankar","Himalaya"));
return list;
}
}
Output
Use the URL http://localhost:8080/spring4-1/blog1. Output in console
17:52:34.787 [http-nio-8080-exec-4] DEBUG o.s.w.s.m.m.a.RequestResponseBodyMethodProcessor - Written [[com.concretepage.bean.Writer@7442d900, com.concretepage.bean.Writer@707d5350, com.concretepage.bean.Writer@357fd33b]] as "application/json;charset=UTF-8" using [org.springframework.http.converter.json.GsonHttpMessageConverter@b6f5aad]
[
{
"name": "Ram",
"location": "Ayodhya"
},
{
"name": "Krishna",
"location": "Mathura"
},
{
"name": "Shankar",
"location": "Himalaya"
}
]
