My project used spring-boot (1.4.0.release) and mybatis-spring-boot-starter. When I try to have some test code for controller, I always get a exception
Caused by: java.lang.IllegalArgumentException: Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required
at org.springframework.util.Assert.notNull(Assert.java:115)
at org.mybatis.spring.support.SqlSessionDaoSupport.checkDaoConfig(SqlSessionDaoSupport.java:75)
at org.mybatis.spring.mapper.MapperFactoryBean.checkDaoConfig(MapperFactoryBean.java:74)
at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:44)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
... 42 more`
But when I comment #MapperScan("com.toby.mapper"), it runs very well.
Here is my example class:
#MapperScan("com.toby.mapper")
#EnableTransactionManagement
#EnableConfigurationProperties(AppConfig.class)
#SpringBootApplication(scanBasePackages = "com.toby.configuration,com.toby.web.controller,com.toby.service,com.toby.dao")
public class Example {
public static void main(String[] args) throws Exception {
//new SpringApplicationBuilder().sources(Example.class).run(args);
SpringApplication application=new SpringApplication(Example.class);
application.addInitializers(new PropertyPasswordDecodingContextInitializer());
application.run(args);
}
}
Here is my test code:
package com.toby.web.controller;
import com.toby.common.config.AppConfig;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
/**
* Created by Toby on 2016/8/10.
*/
#RunWith(SpringRunner.class)
#WebMvcTest(value = MyRestController.class)
public class MyRestControllerTests {
#Autowired
private MockMvc mvc;
#MockBean
private AppConfig appConfig;
#Test
public void testHome() throws Exception {
/*this.mvc.perform(get("/users").accept(MediaType.TEXT_PLAIN))
.andExpect(status().isOk()).andExpect(content().string("Honda Civic"));*/
}
}
I guess you've updated the description or I didn't read it properly the first time. #MapperScan is a mybatis specific annotation that triggers something but is missing some guard of some sort.
We had the same problem in boot actually. Let's say you put #EnableCaching on your main app. Because slicing disables all auto-configurations but a list of specific ones, the cache auto-configuration would not kick in and you'll get an exception because the CacheManager isn't found. To fix that issue, we've started to create some annotation to easily enable those. If you look at WebMbcTest you'll see it's annotated with AutoConfigureCache that's going to provide a dummy no-op cache manager unless specified otherwise.
Your problem is that the mybatis support is a third party integration and there isn't any support for that. Some solutions:
Change #WebMbvcTest to provide the class of another configuration class, effectivly disabling the use of your main spring boot app. Of course that class shouldn't define the #MapperScan annotation
Move the MapperScan (and anything that's not required with slicing) to another Configuration class. It could be a class in the same package as your app. Slicing won't scan those by default so you'll be fine. It's by far the easiest
Create an issue in the mybatis support so that they improve the auto-configuration to back-off (prevent this exception). I am not sure that's possible actually
Long story short, since #MapperScan is a way to tell mybatis to scan your entities, maybe you shouldn't add it on your main boot app if you use slicing. Because your #WebMbcTest doesn't want to use that obviously.
Related
In an interview i was asked by the interviewer that "How does Spring know where to search for Components or Beans?".
As I was not aware about the internal flow details I was not able to answer the question properly.
I said through #Component and #Bean we can find. But the interviewer was not happy with the question.
If anybody knows please share your knowledge. TIA
I love to nswer interview questions. Read below...
#ComponentScan
If you understand Component Scan, you understand Spring.
Spring is a dependency injection framework. It is all about beans and wiring in dependencies.
The first step of defining Spring Beans is by adding the right annotation — #Component or #Service or #Repository.
However, Spring does not know about the bean unless it knows where to search for it.
This part of “telling Spring where to search” is called a Component Scan.
You define the packages that have to be scanned.
Once you define a Component Scan for a package, Spring would search the package and all its sub packages for components/beans.
Defining a Component Scan
If you are using Spring Boot, check the configuration in Approach 1.
If you are doing a JSP/Servlet or a Spring MVC application without
using Spring Boot, use Approach 2.
Approach 1: Component Scan in a Spring Boot Project
If your other package hierarchies are below your main app with the #SpringBootApplication annotation, you’re covered by the implicit Component Scan.
If there are beans/components in other packages that are not sub-packages of the main package, you should manually add them as #ComponentScan
Consider below class
package com.in28minutes.springboot.basics.springbootin10steps;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
#SpringBootApplication
public class SpringbootIn10StepsApplication {
public static void main(String[] args) {
ApplicationContext applicationContext =
SpringApplication.run(SpringbootIn10StepsApplication.class, args);
for (String name: applicationContext.getBeanDefinitionNames()) {
System.out.println(name);
}
}
}
#SpringBootApplication is defined in the SpringbootIn10StepsApplication class which is in the package com.in28minutes.springboot.basics.springbootin10steps
#SpringBootApplication defines an automatic Component Scan on the package com.in28minutes.springboot.basics.springbootin10steps.
You are fine if all your components are defined in the above package or a sub-package of it.
However, let’s say one of the components is defined in package com.in28minutes.springboot.somethingelse
In this case, you would need to add the new package into Component Scan.
You have two options:
Option 1:
#ComponentScan(“com.in28minutes.springboot”)
#SpringBootApplication
public class SpringbootIn10StepsApplication {...}
Option 2:: Define as array
#ComponentScan({"com.in28minutes.springboot.basics.springbootin10steps","com.in28minutes.springboot.somethingelse"})
#SpringBootApplication
public class SpringbootIn10StepsApplication {...}
Approach 2: Non-Spring Boot Project
Option 1:
#ComponentScan(“com.in28minutes)
#Configuration
public class SpringConfiguration {...}
Option 2:
#ComponentScan({"com.in28minutes.package1","com.in28minutes.package2"})
#Configuration
public class SpringConfiguration {...}
XML application context:
<context:component-scan base-package="com.in28minutes" />
Specific multiple packages:
<context:component-scan base-package="com.in28minutes.package1, com.in28minutes.package2" />
The IoC (Inversion of Control) container, represented in Spring by the class ApplicationContext, is the brain behind all of it. It all comes down to using reflection in a really powerful way.
To simplify, let's consider the following steps (all done through reflection):
Search all classes in the classpath
From those classes, get all classes annotated with #Component
For each class annotated with #Component, create a new instance of that class
Check for dependencies, i.e, for each created instance, check all fields annotated with #Autowired and create an instance for each one of them.
Keep everything in the context so they can be used later.
The remaining of this answer is an oversimplified version of how this happens as if we did it ourselves. Thankfully, Spring exists and we don't need to do this ourselves.
The annotations
#Retention(RetentionPolicy.RUNTIME)
public #interface Node {}
#Retention(RetentionPolicy.RUNTIME)
public #interface Wire { }
Some annotated classes for testing
#Node
public class ServiceA {
#Wire
private ServiceB serviceB;
public void doAStuff() {
System.out.println("A stuff");
serviceB.doBStuff();
}
}
#Node
public class ServiceB {
public void doBStuff() {
System.out.println("B stuff");
}
}
The IoC Container
import org.reflections.Reflections;
/* dependency org.reflections:reflections:0.9.12 */
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
public class IoC {
private final Map<Class<?>, Object> allNodes = new HashMap<>();
public void start() {
Reflections reflections = new Reflections(IoC.class.getPackageName());
Set<Class<?>> nodeClasses = reflections.getTypesAnnotatedWith(Node.class);
try {
for (Class<?> c : nodeClasses) {
Object thisInstance = c.getDeclaredConstructor().newInstance();
for (Field f : c.getDeclaredFields()) {
f.setAccessible(true);
if (f.getDeclaredAnnotation(Wire.class) != null) {
Object o = f.getType().getDeclaredConstructor().newInstance();
f.set(thisInstance, f.getType().cast(o));
}
}
allNodes.put(c, thisInstance);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public <T> T getNodeByType(Class<T> cls) {
return cls.cast(allNodes.get(cls));
}
}
And the main class to get it all started.
public class Application {
public static void main(String[] args) {
IoC ioc = new IoC();
ioc.start();
ServiceA serviceA = ioc.getNodeByType(ServiceA.class);
serviceA.doAStuff();
}
}
This will output:
A stuff
B stuff
Of course, Spring is a lot more powerful (and robust) than this. It allows for custom package scanning using #ComponentScan, beans of the same type with different names, singleton/prototype scoped beans, constructor wiring, properties files injection, amongst many other things. When it comes to Spring Boot, the #SpringBootApplication annotation make sure it finds and wire all #Controller annotated classes and set up a Netty/Jetty/Tomcat embedded server to listen to the requests and redirect to the proper controller based on the annotated types.
Well where to search for the beans is defined by the #ComponentScan which can be annotated on the #Configuration class that is used to bootstrap Spring.
For example , it has an attribute called scanBasePackages which tells Spring to scan the beans (A class that is annotated with #Component or its sterotypes such as #Service , #Repository , #Controller etc. ) from certain packages and its sub-packages only.
Then for each bean that are registered , it goes on see if there are any methods annotation with #Bean.If yes, also register them as beans.
New to Spring and AOP programming. Working on a spring AOP tutorial to write aspects that intercept method calls. Would like to enable time logging.
As instructed by the tutorial I created a custom annotation for logging and an aspect to define what should be done when this annotation is called.
The code below is the TrackTime annotation:
package com.in28minutes.springboot.tutorial.basics.example.aop;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
public #interface TrackTime {}
However Eclipse is displaying the errors –
“Element Cannot be Resolved as Variable/Retention Cannot be resolved to a variable”
I then created an aspect called MethodExecutionCalculationAspect with the ‘TrackTime’ annotation.
#Around("#annotation(com.in28minutes.springboot.tutorial.
basics.example.aop.TrackTime)")
MethodExecutionCalculationAspect
package com.in28minutes.springboot.tutorial.basics.example.aop;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Configuration;
#Aspect
#Configuration
public class MethodExecutionCalculationAspect {
private Logger logger = LoggerFactory.getLogger(this.getClass());
#Around("#annotation
(com.in28minutes.springboot.tutorial.basics.example.aop.TrackTime)")
public void around(ProceedingJoinPoint joinPoint) throws Throwable {
long startTime = System.currentTimeMillis();
joinPoint.proceed();
long timeTaken = System.currentTimeMillis() - startTime;
logger.info("Time Taken by {} is {}", joinPoint, timeTaken);
}
}
#Around uses an around advice. It intercepts the method call and uses joinPoint.proceed() to execute the method.
#annotation(com.in28minutes.springboot.tutorial.basics.example.aop.TrackTime) is the pointcut to define interception based on an annotation — #annotation
followed by the complete type name of the annotation.
Once I correct the annotation and the advice, I’m hoping to use the annotation on methods for time tracking. as shown below:
#Service
public class Business1 {
#TrackTime
public String calculateSomething(){
Any help would be appreciated.
Information about the project is as follows:
SpringBootTutorialBasicsAplication.java:
The Spring Boot application class generated with Spring Initializer. This class acts as the launching point for the application.
• pom.xml: Contains all the dependencies needed to build this project using Spring Boot Starter AOP.
• Business1.java, Business2.java, Dao1.java, Dao2.java: Business classes are dependent on DAO classes.
• We would write aspects to intercept calls to these business and DAO classes.
• AfterAopAspect.java: Implements a few After advices.
• UserAccessAspect.java: Implements a Before advice to do an access check.
• BusinessAopSpringBootTest.java: The unit test that invokes the business methods.
• Maven 3.0+ is your build tool
• Eclipse.
• JDK 1.8+
Your TrackTime is missing imports for RetentionPolicy and Target.
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
i have a Spring Boot project which has some external packages i need to import as Beans in the main application.
So i have my main application in com.package.app package and some classes (among which some repositories) in com.package.commons package.
In order to take these beans i have my main class annotated as follows:
#SpringBootApplication
#ComponentScan({ "com.package.commons" ,"com.package.app"})
#EnableScheduling
#EnableAsync
public class EmanagerApplication extends SpringBootServletInitializer{
public static void main(String[] args) {
SpringApplication.run(EmanagerApplication.class, args);
}
}
But when i launch the application it may occur (not always but very ofter) that the start up fails with these kind of error:
Description:
Field repository in com.package.commons.service.BrandService required a bean of type 'com.package.commons.persistence.repository.BrandRepository' that could not be found.
Action:
Consider defining a bean of type 'com.package.commons.persistence.repository.BrandRepository' in your configuration.
My BrandRepository is annotated with #Repository and the service class with #Service
The really strange thing is that if i keep launching the app at the end it stars... but there is no reason for it...
If you're using JPA, you'll also need the #EnableJpaRepositories annotation.
Also consider to use #EnableTransactionManagement to enable declarative transaction handling.
E.g. use something like the following in the same package or a parent package where you have your JPA entities and JPA repositories (untested):
import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.JpaProperties;
import org.springframework.boot.autoconfigure.transaction.TransactionManagerCustomizers;
import org.springframework.orm.jpa.vendor.AbstractJpaVendorAdapter;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.jta.JtaTransactionManager;
#Configuration
#EntityScan
#EnableJpaRepositories
#EnableTransactionManagement
public class HibernateConfig extends JpaBaseConfiguration {
public HibernateConfig(DataSource dataSource, JpaProperties properties, ObjectProvider<JtaTransactionManager> jtaTransactionManager,
ObjectProvider<TransactionManagerCustomizers> transactionManagerCustomizers) {
super(dataSource, properties, jtaTransactionManager, transactionManagerCustomizers);
}
#Override
protected AbstractJpaVendorAdapter createJpaVendorAdapter() {
return new HibernateJpaVendorAdapter();
}
#Override
protected Map<String, Object> getVendorProperties() {
return new HashMap<>();
}
}
And don't forget to annotate your #Service classes also with #Transactional.
If you confirm that the Application which with the startup method of this application is good, and confirm the #ComponentScan is good also. And the configuration file yaml or properties of JPA also good.
How about trying extends JPA Repository like this:
public class xxxResponsitory extends JpaRepository<T, E>{
...
}
Cause JpaRepository has already annotated with #Repository annotation, T means the type of Primary Key, I always use Integer or Long, autoboxing type. E means the main type of this repository.
Make an example:
Now we have an Entity type named User, the Primary key type of User is Long, I would write the repository like this:
public class UserRepository extends JpaRepository<Long, User>{
...
}
Don't need annotated anything, then, In the service class, #Autowried UserRepository, everything is good to run. But make sure the things that I talk at the start of my answer.
Hope this can help you.
Context: I have a project with some utilities to do things like data fixing. Each utility is a Java application, i.e. class with main() method. I want to define them as Spring Boot applications so I can use the ApplicationRunner and ApplicationArguments facility. The Spring configuration is defined via annotations in a shared configuration class. I've put a minimal example of this setup below.
Expectation: if I call SpringApplication.run(SomeClass.class, args) where SomeClass is an ApplicationRunner, it runs the run() on that class and not on any other classes that may be in the app context.
What actually happens: it calls all ApplicationRunners that it has in the context.
Why? I understood SpringApplication.run(Class, String[]) to mean, "run this class" whereas it appears to mean "load an app context from this class and run anything you can find in it". How should I fix it to run only 1 class? I don't mind if my other application class isn't in the app context, because all the configuration I need is in the shared config class. But I don't want to have to edit code (e.g. add or remove annotations) according to which class I need to run.
Minimal example:
A Spring config class (shared):
package com.stackoverflow.example;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class ExampleSpringConfig {
/** Some bean - just here to check that beans from this config are injected */
#Bean public FooService fooService () {
return new FooService();
}
}
Two application classes
package com.stackoverflow.example;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import javax.annotation.Resource;
#SpringBootApplication
public class SomethingJob implements ApplicationRunner {
#Resource private FooService fooService;
public void run(ApplicationArguments args) throws Exception {
System.out.println("Doing something"); // do things with FooService here
}
public static void main(String[] args) {
SpringApplication.run(SomethingJob.class, args);
}
}
and another that is identical except that it prints "Doing something else".
Output:
[Spring Boot startup logs...]
Doing something else
Doing something
[Spring Boot shutdown logs...]
Firstly, only one class should be annotated with #SpringBootApplication. As you've noticed in your answer, this defines the external "main" entry point. I would recommend this is a different class to your ApplicationRunner classes for clarity and conceptual separation.
To only have some but not all runners run, I've done this by parsing the arguments, and quickly exiting from the runner which should not be called. e.g.
package com.stackoverflow.example;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import javax.annotation.Resource;
#Component
public class SomethingJob implements ApplicationRunner {
#Resource private FooService fooService;
public void run(ApplicationArguments args) throws Exception {
if (!args.containsOption("something")) return
System.out.println("Doing something"); // do things with FooService here
}
}
That way you can do java -jar myjar.jar --something or java -jar myjar.jar --something-else depending which one you want to be run.
I found a workaround while experimenting with my minimal example.
#SpringBootApplication is just an alias for #ComponentScan, #EnableAutoConfiguration and #Configuration. By applying them separately, I discovered that it's the #Configuration annotation that causes this behaviour. If I only apply the other 2, I don't get the issue.
I guess this is because #Configuration means "I'm a configuration class, and any beans I define should be pulled into the context during component scan" and although this class doesn't define an ApplicationRunner, it is one, which has the same effect. Therefore if you have 2 such beans on the classpath, they both get pulled into the app context.
Without #Configuration, the bean you want to run still gets registered since it's referenced by the call to run(), but other ApplicationRunners on the classpath don't.
This fixes my immediate problem by making sure I only have one ApplicationRunner in my app context. But it doesn't answer the wider question, "If I do have several ApplicationRunners, how do I tell Spring Boot which one to run?" So I'd still appreciate any more complete answer or suggestions for a different approach.
In Spring what is the best way to run a bunch of test methods on an object but reset/re-inject the object before each new test method invocation?
I have tried to do in the code below but with my current logic the object gets created and injected only once..
package com.bidtracker;
import org.junit.Test;
import org.junit.runner.RunWith;
import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.is;
import com.bidtracker.iface.BidTracker;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration
public class BidTrackerTest {
#Autowired
BidTracker tracker;
#Test
public void shouldReturnHighestBidAmount1(){
tracker.bidOnItem("itemB", "user1", 105);
assertThat(tracker.getHighestBid("itemB").getAmount(),is(Integer.valueOf(105)));
}
#Test
public void shouldReturnHighestBidAmount2(){
tracker.bidOnItem("itemB", "user1", 39);
tracker.bidOnItem("itemB", "user1", 50);
assertThat(tracker.getHighestBid("itemB").getAmount(),is(Integer.valueOf(50)));
}
}
The issue here is that Spring test support by default caches the application context and will reuse the cached context if elements of the key match up(context name(s), active profiles etc). To ask Spring to remove the context from the cache you can mark the test with #DirtiesContext annotation (at the method level or test class level).
JUnit has the #Before annotation, you can use that to do any initialization before each test.
However, I am curious about your case. Here's from the #Test documentation:
The Test annotation tells JUnit that the public void method to which
it is attached can be run as a test case. To run the method, JUnit
first constructs a fresh instance of the class then invokes the
annotated method. Any exceptions thrown by the test will be reported
by JUnit as a failure. If no exceptions are thrown, the test is
assumed to have succeeded.
I'm guessing that the issue is that the bean is a singleton. It actually gets injected again, but if it's been modified you're using the same thing. You can try the #DirtiesContext annotation.