直接进入主题了哈

1）、编写国际化配置文件

a、在IDEA的resources文件夹下创建il8n，在il8n下创建login文件夹；

b、在login文件下创建login.properties、login_zh_CN.properties、login_en_US.properties；

login.properties：代表默认显示的语种，login_zh_CN.properties：切换为页面显示中文，login_en_US.properties:切换为页面显示英文。

如果要显示更多的语言的，则需要自己定义更多的properties文件

c、创建文件后选择 login_zh_CN.properties、login_en_US.properties任意一个文件，点击下方的Resource Bundle

2）、修改配置文件-引入

在application.properties中添加

spring.messages.basename=i18n.login

3）、去页面获取国际化的值；

#{}中的内容表示国际化处理

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
		<meta name="description" content="">
		<meta name="author" content="">
		<title>Signin Template for Bootstrap</title>
		<!-- Bootstrap core CSS -->
		<link href="asserts/css/bootstrap.min.css" rel="stylesheet">
		<!-- Custom styles for this template -->
		<link href="asserts/css/signin.css" rel="stylesheet">
	</head>

	<body class="text-center">
		<form class="form-signin" action="dashboard.html">
			<img class="mb-4" src="asserts/img/bootstrap-solid.svg" alt="" width="72" height="72">
			<h1 class="h3 mb-3 font-weight-normal" th:text="#{login.tip}">Please sign in</h1>
			<label class="sr-only">Username</label>
			<input type="text" class="form-control" th:placeholder="#{login.userName}" required="" autofocus="">
			<label class="sr-only">Password</label>
			<input type="password" class="form-control" th:placeholder="#{login.password}" required="">
			<div class="checkbox mb-3">
				<label>
          <input type="checkbox" value="remember">  [[#{login.remember}]]
        </label>
			</div>
			<button class="btn btn-lg btn-primary btn-block" th:text="#{login.btn}" type="submit">Sign in</button>
			<p class="mt-5 mb-3 text-muted">© 2017-2018</p>
			<a class="btn btn-sm" th:href="@{/index.html(l='zh_CN')}">中文</a>
			<a class="btn btn-sm" th:href="@{/index.html(l='en_US')}">English</a>
		</form>
	</body>
</html>

5)、重写 resolveLocale方法-自定义组件

package lhz.lx.demo.component;


import org.springframework.boot.autoconfigure.web.WebMvcProperties;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.LocaleResolver;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Locale;

public class MyLocaleResolver implements LocaleResolver {
    @Override
    public Locale resolveLocale(HttpServletRequest request) {
        String l = request.getParameter("l");
        Locale locale = Locale.getDefault();
        if(!StringUtils.isEmpty(l)){
            String[] split = l.split("_");
            locale = new Locale(split[0],split[1]);
        }
        return locale;
    }

    @Override
    public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {

    }
}

6)、添加自定义组件

package lhz.lx.demo.config;

import lhz.lx.demo.component.MyLocaleResolver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();
    }
}