- Even better configuration management than @Value
- Type-safe Configuration Properties
- http://localhost:8080/dynamic-configuration
- Also look at http://localhost:8080/actuator/#http://localhost:8080/configprops
First Snippet
package com.in28minutes.springboot.configuration;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties("basic")
public class BasicConfiguration {
private boolean value;
private String message;
private int number;
public boolean isValue() {
return value;
}
public void setValue(boolean value) {
this.value = value;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
}
Second Snippet
@Autowired
private BasicConfiguration configuration;
@RequestMapping("/dynamic-configuration")
public Map dynamicConfiguration() {
// Not the best practice to use a map to store differnt types!
Map map = new HashMap();
map.put("message", configuration.getMessage());
map.put("number", configuration.getNumber());
map.put("key", configuration.isValue());
return map;
}
Third Snippet
basic.value: true
basic.message: Dynamic Message
basic.number: 100
Fourth Snippet
basic:
value: true
message: Dynamic Message YAML
number: 100
- Understand Type Safety
***************************
APPLICATION FAILED TO START
***************************
Description:
Binding to target com.in28minutes.springboot.configuration.BasicConfiguration@391b8545 failed:
Property: basic.number
Value: ABC
Reason: Failed to convert property value of type [java.lang.String] to required type [int] for property 'number'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.lang.String] to type [int]
Action:
Update your application's configuration
<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.in28minutes.springboot</groupId>
<artifactId>first-springboot-project</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.0.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-rest-hal-browser</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
package com.in28minutes.springboot;
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.Profile;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
ApplicationContext ctx = SpringApplication.run(Application.class, args);
}
@Profile("prod")
@Bean
public String dummy() {
return "something";
}
}
package com.in28minutes.springboot.configuration;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties("basic")
public class BasicConfiguration {
private boolean value;
private String message;
private int number;
public boolean isValue() {
return value;
}
public void setValue(boolean value) {
this.value = value;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
}
package com.in28minutes.springboot.controller;
import java.net.URI;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import com.in28minutes.springboot.model.Question;
import com.in28minutes.springboot.service.SurveyService;
@RestController
class SurveyController {
@Autowired
private SurveyService surveyService;
@GetMapping("/surveys/{surveyId}/questions")
public List<Question> retrieveQuestions(@PathVariable String surveyId) {
return surveyService.retrieveQuestions(surveyId);
}
// GET "/surveys/{surveyId}/questions/{questionId}"
@GetMapping("/surveys/{surveyId}/questions/{questionId}")
public Question retrieveDetailsForQuestion(@PathVariable String surveyId,
@PathVariable String questionId) {
return surveyService.retrieveQuestion(surveyId, questionId);
}
// /surveys/{surveyId}/questions
@PostMapping("/surveys/{surveyId}/questions")
public ResponseEntity<Void> addQuestionToSurvey(
@PathVariable String surveyId, @RequestBody Question newQuestion) {
Question question = surveyService.addQuestion(surveyId, newQuestion);
if (question == null)
return ResponseEntity.noContent().build();
// Success - URI of the new resource in Response Header
// Status - created
// URI -> /surveys/{surveyId}/questions/{questionId}
// question.getQuestionId()
URI location = ServletUriComponentsBuilder.fromCurrentRequest().path(
"/{id}").buildAndExpand(question.getId()).toUri();
// Status
return ResponseEntity.created(location).build();
}
}
package com.in28minutes.springboot.model;
import java.util.List;
public class Question {
private String id;
private String description;
private String correctAnswer;
private List<String> options;
// Needed by Caused by: com.fasterxml.jackson.databind.JsonMappingException:
// Can not construct instance of com.in28minutes.springboot.model.Question:
// no suitable constructor found, can not deserialize from Object value
// (missing default constructor or creator, or perhaps need to add/enable
// type information?)
public Question() {
}
public Question(String id, String description, String correctAnswer,
List<String> options) {
super();
this.id = id;
this.description = description;
this.correctAnswer = correctAnswer;
this.options = options;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getDescription() {
return description;
}
public String getCorrectAnswer() {
return correctAnswer;
}
public List<String> getOptions() {
return options;
}
@Override
public String toString() {
return String
.format("Question [id=%s, description=%s, correctAnswer=%s, options=%s]",
id, description, correctAnswer, options);
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Question other = (Question) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
return true;
}
}
package com.in28minutes.springboot.model;
import java.util.List;
public class Survey {
private String id;
private String title;
private String description;
private List<Question> questions;
public Survey(String id, String title, String description,
List<Question> questions) {
super();
this.id = id;
this.title = title;
this.description = description;
this.questions = questions;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public List<Question> getQuestions() {
return questions;
}
public void setQuestions(List<Question> questions) {
this.questions = questions;
}
@Override
public String toString() {
return "Survey [id=" + id + ", title=" + title + ", description="
+ description + ", questions=" + questions + "]";
}
}
package com.in28minutes.springboot.service;
import java.math.BigInteger;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.springframework.stereotype.Component;
import com.in28minutes.springboot.model.Question;
import com.in28minutes.springboot.model.Survey;
@Component
public class SurveyService {
private static List<Survey> surveys = new ArrayList<>();
static {
Question question1 = new Question("Question1",
"Largest Country in the World", "Russia", Arrays.asList(
"India", "Russia", "United States", "China"));
Question question2 = new Question("Question2",
"Most Populus Country in the World", "China", Arrays.asList(
"India", "Russia", "United States", "China"));
Question question3 = new Question("Question3",
"Highest GDP in the World", "United States", Arrays.asList(
"India", "Russia", "United States", "China"));
Question question4 = new Question("Question4",
"Second largest english speaking country", "India", Arrays
.asList("India", "Russia", "United States", "China"));
List<Question> questions = new ArrayList<>(Arrays.asList(question1,
question2, question3, question4));
Survey survey = new Survey("Survey1", "My Favorite Survey",
"Description of the Survey", questions);
surveys.add(survey);
}
public List<Survey> retrieveAllSurveys() {
return surveys;
}
public Survey retrieveSurvey(String surveyId) {
for (Survey survey : surveys) {
if (survey.getId().equals(surveyId)) {
return survey;
}
}
return null;
}
public List<Question> retrieveQuestions(String surveyId) {
Survey survey = retrieveSurvey(surveyId);
if (survey == null) {
return null;
}
return survey.getQuestions();
}
public Question retrieveQuestion(String surveyId, String questionId) {
Survey survey = retrieveSurvey(surveyId);
if (survey == null) {
return null;
}
for (Question question : survey.getQuestions()) {
if (question.getId().equals(questionId)) {
return question;
}
}
return null;
}
private SecureRandom random = new SecureRandom();
public Question addQuestion(String surveyId, Question question) {
Survey survey = retrieveSurvey(surveyId);
if (survey == null) {
return null;
}
String randomId = new BigInteger(130, random).toString(32);
question.setId(randomId);
survey.getQuestions().add(question);
return question;
}
}
package com.in28minutes.springboot;
import java.util.HashMap;
import java.util.Map;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.in28minutes.springboot.configuration.BasicConfiguration;
@RestController
public class WelcomeController {
//Auto wiring
@Autowired
private WelcomeService service;
@Autowired
private BasicConfiguration configuration;
@RequestMapping("/welcome")
public String welcome() {
return service.retrieveWelcomeMessage();
}
@RequestMapping("/dynamic-configuration")
public Map dynamicConfiguration() {
Map map = new HashMap();
map.put("message", configuration.getMessage());
map.put("number", configuration.getNumber());
map.put("value", configuration.isValue());
return map;
}
}
package com.in28minutes.springboot;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
//Spring to manage this bean and create an instance of this
@Component
public class WelcomeService {
@Value("${welcome.message}")
private String welcomeMessage;
public String retrieveWelcomeMessage() {
//Complex Method
return welcomeMessage;
}
}
logging.level.org.springframework: TRACE
logging.level.org.springframework: INFO
logging.level.org.springframework: DEBUG
app.name=in28Minutes
welcome.message=Welcome message from property file! Welcome to ${app.name}
basic.value=true
basic.message=Welcome to in28minutes
basic.number=200