I'm creating a simple rest controller with Spring Boot and the Web dependency. I'm trying to deserialize a JSON body to a test POJO with only 3 fields, but when I attempt to make a POST request, the server responds with a 500 error and the error I get in the console is:
.w.s.m.s.DefaultHandlerExceptionResolver : Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class java.util.LinkedHashMap
All of the code I have written is as follows:
EmailApplication.java:
package com.test.email.app;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
@SpringBootApplication
@ComponentScan(basePackages = { "com.test.email" })
public class EmailApplication {
public static void main(String[] args) {
SpringApplication.run(EmailApplication.class, args);
}
@Bean
public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
return args -> {
System.out.println("----- You're up and running with test-email-app! -----");
};
}
}
EmailController.java:
package com.test.email.controller;
import com.test.email.entity.TestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;
import java.net.URI;
@RestController
public class EmailController {
@RequestMapping(value = "/", method = RequestMethod.GET)
public String index() {
TestEntity entity = new TestEntity();
return "test-email-app index";
}
@RequestMapping(value = "/poster", method = RequestMethod.POST)
public ResponseEntity<String> poster(@RequestBody TestEntity testEntity) {
URI location = URI.create("/poster");
return ResponseEntity.created(location).body(testEntity.getUrl());
}
}
TestEntity.java
package com.test.email.entity;
/**
* An entity for serialization/deserialization testing
*/
public class TestEntity {
public String url;
public int count;
public double height;
public TestEntity() {}
public TestEntity(String url, int count, double height) {
this.url = url;
this.count = count;
this.height = height;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
}
I'm making a POST request with Postman using only the header Content-Type: application/json and with the body:
{ "url": "http://google.com", "count": 3, "height": 2.4 }
I don't know why Spring can't convert from a LinkedHashMap to my POJO. Any help would be appreciated.
Edit:
My pom.xml is as follows:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.test.email</groupId>
<artifactId>test-email-app</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>test-email-app</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
