rest controller not working in spring boot

Question

I have checked most similar questions, and don't find the answer.So I can only post a new question.

I can successfully run my application without errors, but the rest api I write can't be access correctly.I have compared my launch log to the official tutorials, then I have found out I don't have the similar log below:

2017年11月13日 17:37:50.921 INFO 6503 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@2328c243: startup date [Mon Nov 13 17:37:49 CST 2017]; root of context hierarchy
2017年11月13日 17:37:51.061 INFO 6503 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/greeting]}" onto public hello.Greeting hello.GreetingController.greeting(java.lang.String)
2017年11月13日 17:37:51.066 INFO 6503 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017年11月13日 17:37:51.067 INFO 6503 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017年11月13日 17:37:51.126 INFO 6503 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017年11月13日 17:37:51.127 INFO 6503 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017年11月13日 17:37:51.188 INFO 6503 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]

Here are some my java files, Hope anyone can find some keypoint to solve my problem

the main application file:

package com.teachermate;
import com.alibaba.druid.pool.DruidDataSource;
import com.teachermate.entites.TeacherMateSettings;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;
import javax.sql.DataSource;
@SpringBootApplication
@EnableConfigurationProperties({TeacherMateSettings.class})
public class JobScheduleApplication {
 @Autowired
 private Environment env;
 public static void main(String[] args) {
 SpringApplication.run(JobScheduleApplication.class, args);
 }
 @Bean
 public DataSource dataSource() {
 DruidDataSource dataSource = new DruidDataSource();
 dataSource.setUrl(env.getProperty("spring.datasource.url"));
 dataSource.setUsername(env.getProperty("spring.datasource.username"));
 dataSource.setPassword(env.getProperty("spring.datasource.password"));
 dataSource.setInitialSize(2);
 dataSource.setMaxActive(20);
 dataSource.setMinIdle(0);
 dataSource.setMaxWait(60000);
 dataSource.setValidationQuery("SELECT 1");
 dataSource.setTestOnBorrow(false);
 dataSource.setTestWhileIdle(true);
 dataSource.setPoolPreparedStatements(false);
 return dataSource;
 }
}

the controller file:

@RestController
@RequestMapping(path = "/test")
public class TestController {
 @RequestMapping(method = RequestMethod.GET)
 public JSONObject HelloWorld() {
 JSONObject res = new JSONObject();
 LOGGER.info("HelloWorld Test!");
 res.put("data", "hello world!");
 res.put("errCode", 0);
 return res;
 }
}

the pom.xml:

<?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.teachermate</groupId>
 <artifactId>job-scheduler</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>
 <name>jobSchedule</name>
 <description>job schedule for teachermate</description>
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>1.5.7.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-data-redis</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-jdbc</artifactId>
 <exclusions>
 <exclusion>
 <groupId>org.apache.tomcat</groupId>
 <artifactId>tomcat-jdbc</artifactId>
 </exclusion>
 </exclusions>
 </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>
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-context-support</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-configuration-processor</artifactId>
 <optional>true</optional>
 </dependency>
 <dependency>
 <groupId>com.alibaba</groupId>
 <artifactId>fastjson</artifactId>
 <version>1.2.39</version>
 </dependency>
 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <version>5.1.30</version>
 </dependency>
 <dependency>
 <groupId>org.quartz-scheduler</groupId>
 <artifactId>quartz</artifactId>
 <version>2.2.1</version>
 </dependency>
 <dependency>
 <groupId>com.google.guava</groupId>
 <artifactId>guava</artifactId>
 <version>23.2-jre</version>
 </dependency>
 <dependency>
 <groupId>org.apache.httpcomponents</groupId>
 <artifactId>httpclient</artifactId>
 <version>4.3.6</version>
 </dependency>
 <dependency>
 <groupId>com.alibaba</groupId>
 <artifactId>druid</artifactId>
 <version>1.0.19</version>
 </dependency>
 </dependencies>
 <build>
 <plugins>
 <plugin>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-maven-plugin</artifactId>
 <configuration>
 <executable>true</executable>
 </configuration>
 </plugin>
 </plugins>
 </build>
</project>

BTW, the rest api works fine before I add some code or library(like druid).But I don't know what cause it, can anyone help? Or can anyone show me a way to debug it? Thanks!

If you need any other information, just tell me in the comments.

---

update

I have modified the controller in official tutorials to

@RestController
@RequestMapping(path = "/test")
public class GreetingController {
 private static final String template = "Hello, %s!";
 private final AtomicLong counter = new AtomicLong();
 @RequestMapping("/greeting")
 public Greeting greeting(@RequestParam(value="name", defaultValue="World") String name) {
 return new Greeting(counter.incrementAndGet(),
 String.format(template, name));
 }
 @RequestMapping(method = RequestMethod.GET)
 public JSONObject HelloWorld() {
 JSONObject res = new JSONObject();
 res.put("data", "hello world!");
 res.put("errCode", 0);
 return res;
 }
}

it works fine!

• shakeel: Add the test controller in the same package as GreetingController and try
• Gurkan Yesilyurt: Maybe there is a conflict between fastjson and jackson in spring-boot-web . Please again remove fastjson dependency and check whether it works well or not.
• Liu Wenzhe: @GurkanYesilyurt the rest api works fine before, at that time I have used the fastjson library
• Liu Wenzhe: @shakeel I have tried, it works fine

Answer 1

I finally figured it out.

I write a while loop in a method which has the @PostConstruct Annotation.It must block the spring main process, causing the rest controller not being loaded.

How foolish am I.

• Abhijith Madhav: Same here. I was starting a kstreams topology in the @PostConstruct which would run on indefinitely

Answer 2

Could it be because it cant find the controller ? If yes, may you try this using @ComponentScan ? @ComponentScan tells Spring to look for other components, configurations, and services in the hello package, allowing it to find the controllers.

@SpringBootApplication
@ComponentScan(basePackageClasses = TestController.class)
@EnableConfigurationProperties({TeacherMateSettings.class})
public class JobScheduleApplication {
//Your code here
}

• Liu Wenzhe: I add @ComponentScan(basePackageClasses = TestController.class, basePackages = "com.teachermate"), because I have other component need to be register as beans. But it didn't work

Answer 3

So basically your application main method is not able to identify the controller,service,entity etc. First please make sure you are using for their respective classes. like @Restcontroller for your controller class

@RestController
@service
@Entity
@JPARepository

Also, Make sure you are asking the spring boot application to check for these classes in the different packages

@ComponentScan({"com.funky.classes.controller","com.funky.classes.service"})
@EntityScan("com.funky.classes.model")
@EnableJpaRepositories("com.funky.classes.repository")
@SpringBootApplication()... 

Answer 4

Create a person class to test:

public class Person{
private String name;
private String nickname;
//getters and setters...
}

In your method of controller, try this:

 @GetMapping(value ="/test", consumes = {MediaType.APPLICATION_JSON_VALUE })
 public ResponseEntity<?> helloWorld() {
 Person person = new Person();
 person.setName("test");
 person.setNickname("test2");
 return ResponseEntity.status(HttpStatus.OK).body(person);
 }

• akshaya pandey: what is need to add person class here. You can directly hit the url and check.

Answer 5

There are a couple of things missing here. First, you need to add RequestMapping to the defined function and for returning the JSONObject, you need to use the @ResponseBody Annotation along with ResponseEntity as the return type of the function Example Code:

@RequestMapping(value = "/testing", method = RequestMethod.GET, consumes = MediaType.APPLICATION_JSON)
public @ResponseBody ResponseEntity<JSONObject> HelloWorld() {
 JSONObject res = new JSONObject();
 LOGGER.info("HelloWorld Test!");
 res.put("data", "hello world!");
 res.put("errCode", 0);
 return ResponseEntity.status(HttpStatus.OK).body(res);
}

The @RequestMapping Annotation can used on both Function level as well as Class Level. Class Level Annotation value should be prepended to all function @RequestMapping Annotation values in the final REST Endpoint.

• M. Deinum: When using @RestController the @ResponseBody is implied.

Answer 6

Good day !

 The @RequestMapping annotation should be made in this way
@RestController
public class TestController {
 @RequestMapping(value = "/test", method = RequestMethod.GET)
 public JSONObject HelloWorld() {
 JSONObject res = new JSONObject();
 LOGGER.info("HelloWorld Test!");
 res.put("data", "hello world!");
 res.put("errCode", 0);
 return res;
 }
}

but that way you get the same result

@RestController
public class TestController {
 @RequestMapping(value = "/test", method = RequestMethod.GET, 
 produces = MediaType.APPLICATION_JSON_VALUE )
 public HashMap HelloWorld() {
 HashMap<String, String> res = new HashMap<String, String>(); 
 res.put("data", "hello world");
 res.put("errorCode", "0");
 return res;
 }
}

url -> localhost:{port}/test

References:

• http://spring.io/guides/tutorials/bookmarks/#_getting_started

• https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#getting-started-first-application-code

• M. Prokhorov: The second code block will not compile because of differences in return type.

Answer 7

I had the same problem with springboot 3.0.1, especially ones which use tomcat 10.14. You will have to use this format on your springboot application class if not it will throw white label page.

here is the format to try. Put on the springboot class application

@EnableAutoConfiguration
@SpringBootApplication
@AutoConfigurationPackage
@ComponentScan(basePackageClasses = {UserResourceController.class, UserService.class, Repo.class})
public class DemoApplication {
 public static void main(String[] args) {
 SpringApplication.run(DemoApplication.class, args);
 }
}

Answer 8

@SpringBootApplication annotation comes with package scanning and all we don't need to repeat it. On your controllers, add requestpath separately as below,

@RestController()
@RequestMapping("/employees")
public class EmployeeController {
 // methods
}
However, if you add ```
@RestController("/employees")```
only to your controllers that won't work. 

Answer 9

Try applying the request mapping annotation as described below.

@RestController
public class TestController {
 @RequestMapping(method = RequestMethod.GET)
 @RequestMapping(path = "/test")
 public JSONObject HelloWorld() {
 JSONObject res = new JSONObject();
 LOGGER.info("HelloWorld Test!");
 res.put("data", "hello world!");
 res.put("errCode", 0);
 return res;
 }
}

Also, check this link below for more examples: http://www.baeldung.com/spring-requestmapping