There is an embedded tomcat in Spring Boot. We can not edit web.xml to add a filter. In this page I will show you how to add filter in Spring Boot without web.xml. I use WebFilter annotation to add filter. After adding this annotation you have to add ServletComponentScan annotation to make Spring Boot find this filter.
Use following command to change the push url of repository.
If you want copy content and paste multiple times, "register" is good way to do this. After select the content you want to copy press "ay. This command save the content to the register named a. Use following command to paste this content to the place you want.
In Vim we can use j and k to move the cursor to specified line and press D or dd to delete current. You can also use next command to delete specified line.
I want sync remote tags to local. After google I got some commends. Unfortunately, those commands sometimes work and sometimes don't work. I think this may be related to the environment and the version of git. Eventually I finally found a universal solution.
When we download file from remote server. We need to check the integrity of the file. In general, the website will provide the md5 value of the downloaded file. In this page I will show you how to use apache-commons-codec to get the md5 of file.
okhttp is one of best network framework. In this page I will show your how to use it post json to remote server. The code is here.
When I use thrift generate classes I got IncompatibleClassChangeError. This error means the class you depends has changed. Let's say your project depend on ClassA.class. When ClassA.class upgrades to new version (add some new methods or fields). It's name doesn't change. You project can use both old and new version of this class. This is "Binary Compatibility". But when the new version change one static field to no-static. IncompatibleClassChangeError will be thrown.
There are many practical methods in the Collectors class. mapping method is one of them. In this page I will show you how to use mapping method in Collectors. Let's say you have a list of users(List). Let's say you want to group these users by age. The code will be like this.
It is very convenient to use CompleteFuture to implement concurrency in java8. I will show you how to use it in this page. Let's say you need to query someone's information(address, company name, family). Every query need 300ms. If you request the information one by one, you will need about 1 second. If you use the CompleteFuture concurrent request, it only takes 300 milliseconds.
It is easy to install docker in CentOS. Open the official website of docker copy commands and paste them in your terminal. now docker only supports CentOS7+. Before installing you need make sure your CentOS version is higher than 7. For the detail you can click here
We can use redis-cli to connect redis sever and execute command. Today I want to execute multiple commands. After connecting redis server I copy multiple commands and paste them in redis-cli. I got error message. My commands are like following.
Generally we call methods in a synchronous manner. In some cases we need to call methods asynchronously. @Async can help us call methods asynchronously when using Spring Boot. Before using @Async we need to add an @EnableAsync on the startup class. Here's a simple example that shows how to use @Async to implement asynchronous method calls.
Recently I am writing a program that processes messages in the background. The program quits when I start 10 threads. I checked all the exception stack information and found no errors. I tried to find this "error" on Google and didn't find any useful information. Why my program or my thread stop? I read my code line by line. It seems like following.
The default data directory of MySQL is /var/lib/mysql. If there is no disk space for this directory we need to move data to another directory(another fileSystem). In my environment I install MySQL by yum command. The /var/lib/mysql directory is mounted on / and there is no more space for data. I change data directory by using these following commands.