spring-boot-2.0.3 not the same series of internationalization

Objective

For spring boot, there are a lot of high-quality series of tutorials online, I will no longer swim (actually worry about no one else to write good, haha ha!) ）。 But still want to rub spring boot heat, even if not consider microservices, spring boot has a lot of advantages, such as automated configuration, series starters simplifies maven dependency management. This series is mainly to integrate some of the functions involved in the work with the Spring boot integration (work is useless to spring-boot).

Maven-ssm-web in the content will be integrated into the past, several recent blogs will first introduce some of the maven-ssm-web not in the new content (because more familiar!) ); Maven-ssm-web more recently, if a friend still needs, will continue to update; the Spring Boot Integration project is:spring-boot-integrate, the series works are: spring-boot-2.0.3.

This series of projects are based on spring-boot-2.0.3; This is the first article, first of all, to talk about the internationalization of spring boot, Project address:spring-boot-i18n

Basic version

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 .lee</groupid> <artifactid>spring-boot-i18n</artifactid > <version>1.0-SNAPSHOT</version> <properties> <java.version>1.8</java.version&    Gt </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactid    >spring-boot-starter-parent</artifactId> <version>2.0.3.RELEASE</version> </parent>            <dependencies> <dependency> <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactid>spring-boot-starter-thymeleaf </artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactid>spring-boot-maven-plugin</arti factid> </plugin> </plugins> </build></project>

Application.yml

Server:   8880Spring:  #国际化配置  messages:    encoding:utf-8    basename:i18n/Messages  # Thymeleaf configuration  thymeleaf:    false

I18nconfig.java

 PackageCom.lee.i18n.config;ImportOrg.springframework.context.annotation.Bean;Importorg.springframework.context.annotation.Configuration;ImportOrg.springframework.web.servlet.LocaleResolver;ImportOrg.springframework.web.servlet.config.annotation.InterceptorRegistry;ImportOrg.springframework.web.servlet.config.annotation.WebMvcConfigurer;ImportOrg.springframework.web.servlet.i18n.CookieLocaleResolver;Importorg.springframework.web.servlet.i18n.LocaleChangeInterceptor; @Configuration Public classI18nconfig {//Configuring the cookie Language parser@Bean Publiclocaleresolver Localeresolver () {cookielocaleresolver resolver=NewCookielocaleresolver (); Resolver.setcookiemaxage (3600);//cookie effective duration, in secondsResolver.setcookiename ("Language");//set the stored cookie name to language        returnResolver; }    //Configure an interceptor to intercept changes in internationalized languages@Bean Publicwebmvcconfigurer Webmvcconfigurer () {return NewWebmvcconfigurer () {//Interception Device@Override Public voidaddinterceptors (Interceptorregistry registry) {Registry.addinterceptor (NewLocalechangeinterceptor ()). Addpathpatterns ("/**");    }        }; }}

View Code

Logincontroller.java

 PackageCom.lee.i18n.controller;ImportOrg.springframework.stereotype.Controller;Importorg.springframework.web.bind.annotation.RequestMapping; @Controller Public classLogincontroller {@RequestMapping ("/login")     PublicString Login () {return"Login"; } @RequestMapping ("/index")     PublicString Index () {return"Index"; }}

View Code

Messages.properties

Index.welcome= Welcome Login.username= Login name Login.password= password Login.login= login

Messages_en_us.properties

Index.welcome=welcomelogin.username=Usernamelogin.password=Passwordlogin.login= Login

Messages_zh_cn.properties

Index.welcome= Welcome Login.username= Login name Login.password= password Login.login= login

When the file is configured well (other can go to spring-boot-i18n pull ), are configured well, the project ran up, we come to see the results, whether to achieve the internationalization effect? The answer is YES!

Premium Edition

The basic version has a drawback, is that the international resources are written in a file: Messages*.properties, the content is written in a file has a fatal disadvantage: the larger the file, the more difficult to maintain;

So where's the premium version? You are right, is the resource in a certain nature or function into a resource folder, and then in the Resource folder to decentralize specific resource files, such as

The contents of the changes have been marked, the content of the specific changes can go to spring-boot-i18n pull; Engineering run, let's see the results.

SOURCE Inquiry

From the initialization of the two containers to see the whole process, which is the two containers, one is the spring root container, one is the Spring MVC container, the spring root container is the root context: webapplicationcontext,spring The MVC container is: dispatcherservlet;

Spring Root Container initialization

Let's start with the main function, such as

Initmessagesource (): Initializes an internationalized resource, finishbeanfactoryinitialization (beanfactory) instantiates non-deferred initialization of the Bean;spring container initialization content is still very much, Interested friends can follow the breakpoint debugging detailed look at the initialization of the session process; All the beans are defined in the Defaultlistablebeanfactory beandefinitionmap, Subsequent instances of the bean definition are obtained from BEANDEFINITIONMAP.

Spring MVC container Initialization

We all know that the core class of spring MVC is dispatcherservlet, and we'll start with him, like:

From the Dispatcherservlet inheritance relationship, Httpservletbean inherits the HttpServlet, so the Init method is called when the Web container starts. We can use this as a portal to track the initialization of Dispatcherservlet, and the Initstrategies method in Dispatcherservlet is important, and initlocaleresolver (context) and inithandlermappings (context) and the internationalization of this article is directly related, initlocaleresolver (context) Binds our own defined localeresolver to the Dispatcherservlet attribute Localeresolver; inithandlermappings (context) Add our own new interceptor Localechangeinterceptor to the Dispatcherservlet handlermappings;

Is it a wonderful feeling that some of our custom beans are associated with dispatcherservlet, and our request URL must go through Dispatcherservlet, is that a coincidence? It's obviously not! If you're still confused, I'm sorry! We went on to look down ...

Request process

From Dispatcherservlet's inheritance, the request passes through the Dispatcherservlet Doservice method, Doservice binds the Localeresolver in Dispatcherservlet (that is, the Cookielocaleresolver object we define) to the current request object. Then call Dodispatch to forward the request;

Class inheritance diagram for Localechangeinterceptor

It is known that it inherits the Handlerinterceptor, and rewrite the Prehandle, we start from the Localechangeinterceptor Prehandle method (the request will certainly go through this method) read the source code, interrupt point tracking, as follows

Since the locale parameter can be aware of language changes, it is also possible to load the corresponding resources according to the language, so as to achieve internationalization (how to load the need for everyone to read the source code!) ）

Source reading this end, is not particularly fine, but provides a main process; We strongly recommend that you read the source code when the breakpoint debugging tracking, not easy to lose!

Reference

Do your own spring-boot to strengthen the internationalization function

Chapter Three Dispatcherservlet--the study of SPRINGMVC with Tao