实战：第二十二章：i18n国际化（已实现中文，英文，波兰文）

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">
    <parent>
        <artifactId>common</artifactId>
        <groupId>com.liao</groupId>
        <version>1.0.0</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>common-i18n</artifactId>

    <properties>
        <poi.version>3.9</poi.version>
        <spring.version>5.0.11.RELEASE</spring.version>
        <javax.servlet.version>4.0.1</javax.servlet.version>
        <spring.data.version>2.0.9.RELEASE</spring.data.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-commons</artifactId>
            <version>${spring.data.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${javax.servlet.version}</version>
        </dependency>
    </dependencies>

</project>

创建配置文件：LocaleConfiguration

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.i18n.LocaleChangeInterceptor;

/**
 * 语言区域配置
 * @author zhiwei Liao
 */
@Configuration
public class LocaleConfiguration {

    private final String LOCAL_HEAD_NAME = "Locale";

    @Bean
    public WebMvcConfigurer localeInterceptor() {
        return new WebMvcConfigurer() {
            @Override
            public void addInterceptors(InterceptorRegistry registry) {
                LocaleChangeInterceptor localeInterceptor = new LocaleChangeInterceptor();
                localeInterceptor.setParamName(LOCAL_HEAD_NAME);
                registry.addInterceptor(localeInterceptor);
            }
        };
    }
}

创建常量：LanguageConstant

/**
 * @author zhiwei Liao
 * @version 1.0
 * @Description 语言
 * @Date 2021/7/19 18:31
 */

public class LanguageConstant {

    //波兰文
    public static final String PL = "pl_pl";

    //英文
    public static final String US = "en_us";

    //中文
    public static final String CN = "zh_cn";

    //请求头中设置语言
    public static final String ACCEPT_LANGUAGE = "accept-language";

}

创建工具类：LocaleUtils

import com.liao.common.i18n.constant.LanguageConstant;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.MessageSource;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.security.auth.login.LoginContext;
import javax.servlet.http.HttpServletRequest;
import java.util.Enumeration;
import java.util.Locale;

/**
 * 国际化转换工具
 * @author zhiwei Liao
 */
@Component
public class LocaleUtils {

    private static final Logger log = LoggerFactory.getLogger(LocaleUtils.class);

    private static MessageSource messageSource;

    public LocaleUtils(MessageSource messageSource) {
        LocaleUtils.messageSource = messageSource;
    }

    public static String getMessage(String msgKey) {
        return getMessage(msgKey, null);
    }

    public static String getMessage(String msgKey,Object[] args) {
        try {
            return messageSource.getMessage(msgKey, args, LocaleContextHolder.getLocale());
        } catch (Exception e) {
            return msgKey;
        }
    }

    /**
     * @Description 获取当前语言
     * @MethodParameterTypes []
     * @MethodParameters []
     * @MethodReturnType java.util.Locale
     * @Author zhiwei Liao
     * @Date 2021/7/19 18:43
     **/
    public static Locale getCurrentLocale() {
        String language = null;
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = ((ServletRequestAttributes) requestAttributes).getRequest();
        Enumeration<String> headerNames = request.getHeaderNames();
        if (headerNames != null) {
            while (headerNames.hasMoreElements()) {
                String name = headerNames.nextElement();
                if(LanguageConstant.ACCEPT_LANGUAGE.equals(name)){
                    Enumeration<String> values = request.getHeaders(name);
                    while (values.hasMoreElements()) {
                        String value = values.nextElement();
                        if(LanguageConstant.PL.equals(value)){
                            language = value;
                        }else if(LanguageConstant.US.equals(value)){
                            language = value;
                        }else if(LanguageConstant.CN.equals(value)){
                            language = value;
                        }
                    }
                }
            }
        }
        log.info("======getCurrentLocale.language:" + language);
        Locale locale = null;
        if(LanguageConstant.PL.equals(language)){
            //波兰文
            locale = new Locale("pl","PL");
//                locale = new Locale("pl_PL");//本地有效，服务器上无效
        }else if(LanguageConstant.US.equals(language)){
            //英文
            locale = Locale.US;
        }else if(LanguageConstant.CN.equals(language)){
            //简体中文
            locale = Locale.SIMPLIFIED_CHINESE;
        }else {
            //请求头中没有语言设置时，默认给英文
            locale = Locale.US;
        }
        log.info("=========locale:" + locale);
        return locale;
    }

}

引用国际化模块的依赖，创建多语言文件
错误提示国际化返回：

log.error(UserinfoConstant.LOGIN_FAILED);
String message = messageSource.getMessage("user.login.failed", null, LocaleUtils.getCurrentLocale());
return ResultData.error(UserCodeConstant.LOGIN_FAILED, message);

测试是否可用：
波兰文：
英文：
中文：