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kandi X-RAY | SpringBoot Summary
kandi X-RAY | SpringBoot Summary
SpringBoot项目初始化 : SpringBoot-Junit : SpringBootSpringData-JPA :
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Top functions reviewed by kandi - BETA
- Configure the HTTP security .
- The entity manager factory bean .
- Gets the value of the pid .
- Gets the value of the companyId property .
- Gets the value of the company property .
- Gets the home screen .
- Gets the name .
- Set the student name .
- Sets the element content .
- Entry point for the demo .
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Community Discussions
Trending Discussions on SpringBoot
QUESTION
I made a consumer and producer class using spring. Now I want the consumer to trigger some api based on the messages sent by producer. How to do that? Please provide solution in JAVA SpringBoot. How to trigger an api from application.yml in consumer?
...ANSWER
Answered 2021-Jun-14 at 18:39when I add @postMapping here then it gives error
You can only add that annotation on REST server methods that handle incoming requests.
You are trying to make an outgoing HTTP call, then you need to use an HTTP Client of your choice, or a Spring RestTemplate
If you are trying to call any internal HTTP endpoint, then you should refactor your code to call methods of the same classes those HTTP resources interact with.
QUESTION
SpringBoot v2.5.1
There is an endpoint requesting a long running process result and it is created somehow
(for simplicity it is Mono.fromCallable( ... long running ... )
.
Client make a request and triggers the publisher to do the work, but after several seconds client aborts the request (i.e. connection is lost). And the process still continues to utilize resources for computation of a result to throw away.
What is a mechanism of notifying Project Reactor's event loop about unnecessary work in progress that should be cancelled?
...ANSWER
Answered 2021-Jun-15 at 09:06fromCallable
doesn't shield you from blocking computation inside the Callable
, which your example demonstrates.
The primary mean of cancellation in Reactive Streams is the cancel()
signal propagated from downstream via the Subscription
.
Even with that, the fundamental requirement of avoiding blocking code inside reactive code still holds, because if the operators are simple enough (ie. synchronous), a blocking step could even prevent the propagation of the cancel()
signal...
A way to adapt non-reactive code while still getting notified about cancellation is Mono.create
: it exposes a MonoSink
(via a Consumer
) which can be used to push elements to downstream, and at the same time it has a onCancel
handler.
You would need to rewrite your code to eg. check an AtomicBoolean
on each iteration of the loop, and have that AtomicBoolean flipped in the sink's onCancel
handler:
QUESTION
I have a Springboot project and I know I can send a application.properties file as a argument, but is this possible using a jar file?
I built my jar file using maven and in my application I have this piece of code that runs the programm if the user sent the argument run.
Is there any method that allows me to set the application properties if I receive it through argument? Or does the override of the file happens automatically as it does when I use the command
mvn spring-boot:run -Dspring.config.location=your.properties
ANSWER
Answered 2021-Jun-14 at 13:12For jar you can either pass one of the properties or the complete or its location as beow.
we can configure the location directly in the command line:
QUESTION
There is a Java 11 (SpringBoot 2.5.1) application with simple workflow:
- Upload archives (as multipart files with size 50-100 Mb each)
- Unpack them in memory
- Send each unpacked file as a message to a queue via JMS
When I run the app locally java -jar app.jar
its memory usage (in VisualVM) looks like a saw: high peaks (~ 400 Mb) over a stable baseline (~ 100 Mb).
When I run the same app in a Docker container memory consumption grows up to 700 Mb and higher until an OutOfMemoryError. It appears that GC does not work at all. Even when memory options are present (java -Xms400m -Xmx400m -jar app.jar
) the container seems to completely ignore them still consuming much more memory.
So the behavior in the container and in OS are dramatically different.
I tried this Docker image in DockerDesktop Windows 10
and in OpenShift 4.6
and got two similar pictures for the memory usage.
Dockerfile
...ANSWER
Answered 2021-Jun-13 at 03:31In Java 11, you can find out the flags that have been passed to the JVM and the "ergonomic" ones that have been set by the JVM by adding -XX:+PrintCommandLineFlags
to the JVM options.
That should tell you if the container you are using is overriding the flags you have given.
Having said that, its is (IMO) unlikely that the container is what is overriding the parameters.
It is not unusual for a JVM to use more memory that the -Xmx
option says. The explanation is that that option only controls the size of the Java heap. A JVM consumes a lot of memory that is not part of the Java heap; e.g. the executable and native libraries, the native heap, metaspace, off-heap memory allocations, stack frames, mapped files, and so on. Depending on your application, this could easily exceed 300MB.
Secondly, OOMEs are not necessarily caused by running out of heap space. Check what the "reason" string says.
Finally, this could be a difference in your app's memory utilization in a containerized environment versus when you run it locally.
QUESTION
I have used Embedded Redis for caching in my springboot application. The redis runs on localhost and default port "6379"
on application start up.
Is there a way to get metrics(memory-used, keyspace_hits, keyspace_misses, etc..) for embedded redis, from outside the application, may be command line or any API
?
PS: I have used Redisson as client to perform cache operations with redis.
Thanks.
...ANSWER
Answered 2021-Jun-14 at 08:47Redis has provided a command line interface : redis-cli
to interact with it and get the metrics. redis-cli can be used on embedded redis as well.
- install command line interface
npm install -g redis-cli - connect to redis running locally(cmd: rdcli -h host -p port -a password )
rdcli -h localhost - use any redis commands
localhost:6379> info memory
#Memory
used_memory:4384744 used_memory_human:4.18M
used_memory_rss:4351856
used_memory_peak:4385608
used_memory_peak_human:4.18M
used_memory_lua:35840
mem_fragmentation_ratio:0.99
mem_allocator:dlmalloc-2.8
Ref: "Installing and running Node.js redis-cli" section of this post https://redislabs.com/blog/get-redis-cli-without-installing-redis-server
QUESTION
I'm trying to provide CloseableHttpClient to Spring Cloud OpenFeign. Spring Cloud Open Feign Documentationsays it supports CloeableHttpClient. Spring documentation doesn't give any example of actually replacing the HTTP client.
Basically, I'm providing SSLContext to the HTTP client and I want Feign to use this SSLContext loaded client. How to inject this CloseableHttpClient into the Feign?
Following is my relevant configuration:
- I'm using SpringBootApp
ANSWER
Answered 2021-Jun-09 at 05:01You need to put @Configuration
on top of FeignConfig
which should make it work I believe.
QUESTION
This is now fixed with SpringBoot 2.5.1
Small question about a warning I am receiving please.
After the release of 2.5.0 of SpringBoot, I just did a version bump from 2.4.x to 2.5.0, without any code change.
Suddenly, on application start up, I am getting
kground-preinit] o.s.h.c.j.Jackson2ObjectMapperBuilder: For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
The thing is, my Springboot all is not a Kotlin app, it is a Java app.
It has nothing Kotlin.
Furthermore, I am not even doing any explicit JSON parsing.
May I ask how I can disable, resolve this warning please?
...ANSWER
Answered 2021-May-23 at 14:57There seems to be a solution here. The idea is to provide extra configuration for Jackson2ObjectMapperBuilderCustomizer
. Sucks that a code change is required but there you have it.
QUESTION
I am working on an application which has 2 modules.
- server module which is SpringBoot.
- ui which is in Angular
I am unable to run any E2E tests for my application as it is not starting before the tests run. I have below defined in the test class which should bring up the application context but it seems it does not.
...ANSWER
Answered 2021-Jun-13 at 16:53The issue was not with the modules. There were 2 issues,
- I was using an older version of Chrome driver for running the tests.
- The E2E tests were trying to access the application using https but the certificates I was using were self signed certificates. To overcome this, I added the below argument to my chromeoptions.
chromeOptions.addArguments("allow-insecure-localhost");
QUESTION
I'm a beginner with spring and I have this little issue. "No property questionId found for type CourseTestCompleteField!" I have 2 model classes that are connected via a one to one join. That 2 model class are:
...ANSWER
Answered 2021-Jun-13 at 06:30Since,This is a query on nested Object. You need to update your query as this.
QUESTION
I have got a Spring Boot project with two data sources, one DB2 and one Postgres. I configured that, but have a problem:
The auto-detection for the database type does not work on the DB2 (in any project) unless I specify the database dialect using spring.jpa.database-platform = org.hibernate.dialect.DB2390Dialect
.
But how do I specify that for only one of the database connections? Or how do I specify the other one independently?
Additional info to give you more info on my project structure: I seperated the databases roughly according to this tutorial, although I do not use the ChainedTransactionManager: https://medium.com/preplaced/distributed-transaction-management-for-multiple-databases-with-springboot-jpa-and-hibernate-cde4e1b298e4 I use the same basic project structure and almost unchanged configuration files.
...ANSWER
Answered 2021-Jun-12 at 23:21Ok, I found the answer myself and want to post it for the case that anyone else has the same question.
The answer lies in the config file for each database, i.e. the DB2Config.java file mentioned in the tutorial mentioned in the question.
While I'm at it, I'll inadvertedly also answer the question "how do I manipulate any of the spring.jpa properties for several databases independently".
In the example, the following method gets called:
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