Fork me on GitHub

使用dropwizard(6)-国际化-easy-i18n


前言

Dropwizard官方文档并没有提供国际化的模块,所以只能自己加。Spring的MessageResource用的很顺手,所以copy过来。

Easy i18n

在整合Dropwizard的时候,多语言貌似只能通过jdk自带的ResourceBundle拿数据。其实也就够了,但在开发过程中发现需要缓存,需要解析占位符等。代码越写越多,显然不是仅仅一个调用就完事的。写的差不多的时候突然觉得和spring context里的message source结构类似。于是,放弃维护已经开始变的复杂的逻辑,直接使用spring。

但选取dropwizard的时候就是摒弃了spring,再拿过来也不好玩了。干脆,抽取Spring context项目的MessageResource相关代码,重写封装了一个library: https://github.com/Ryan-Miao/easy-i18n, 欢迎star。

easy-i18n还是和在Spring项目中相同。

首先,引入依赖,由于github项目的library已经有仓库去维护了,就没费心思放到maven和jcenter了,直接从github上拉取。类库地址为:

1
2
3
4
5
6
<repositories>
<repository>
<id>jitpack.io</id>
<url>https://jitpack.io</url>
</repository>
</repositories>

引入

1
2
3
4
5
<dependency>
<groupId>com.github.Ryan-Miao</groupId>
<artifactId>easy-i18n</artifactId>
<version>1.0</version>
</dependency>

简单使用

#情形一 只有一个Resource Bundle

在resources下新建i18n/messages.properties以及i18n/messages_zh_CN.properties. demo位置:l4dropwizard

然后,调用方法如下:

1
2
3
4
5
6
7
8
9
@Test
public void testI18n(){
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.addBasenames("i18n/messages");
messageSource.setDefaultEncoding("UTF-8");
String index = messageSource.getMessage("index", null, Locale.US);
System.out.println(index);
}

#情形二 我有多个Resource Bundle

实际项目中,由于产品分类,有时候需要创建多个Resource Bundle,这时候也简单,只要创建多个ResourceBundleMessageSource来读取翻译即可。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
public void testI18n2(){
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.addBasenames("i18n/messages");
messageSource.setDefaultEncoding("UTF-8");
String index = messageSource.getMessage("index", null, Locale.US);
System.out.println(index);
ResourceBundleMessageSource messageSource2 = new ResourceBundleMessageSource();
messageSource2.addBasenames("i18n/messages2");
messageSource2.setDefaultEncoding("UTF-8");
String second = messageSource2.getMessage("second", null, Locale.US);
System.out.println(second);
}

#情形三 我有多个Resource Bundle但读取翻译的时候我想一起

有时候,想要读取翻译,可能翻译文件在不同的Resource Bundle,但我指向用一个接口去调用。这时候,做法时候在这几个Resource Bundle的里面添加命名空间,即key要在这几个Resource Bundle里唯一,而不仅仅是本文件唯一。

然后,

1
2
3
4
5
6
7
8
9
public void testI18n2(){
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.addBasenames("i18n/messages", "i18n/messages2");
messageSource.setDefaultEncoding("UTF-8");
String index = messageSource.getMessage("index", null, Locale.US);
System.out.println(index);
}

这种做法,会一次从两个Resource Bundle里寻找翻译,找到即返回。因此,如果有相同的key,将导致只有第一个生效。

#情形4

没有了,你翻译要那么复杂吗。

更多用法,参考测试类:ResourceBundleMessageSourceTest

Demo source

https://github.com/Ryan-Miao/l4dropwizard

本文是基于dropwizard入门之上的演进。

确保依赖都是最新的,或者自行解决版本冲突,比如jackson不同版本之间的类有所不同。

引入easy-i18n

repository url

1
2
3
4
5
6
<repositories>
<repository>
<id>jitpack.io</id>
<url>https://jitpack.io</url>
</repository>
</repositories>

引入

1
2
3
4
5
<dependency>
<groupId>com.github.Ryan-Miao</groupId>
<artifactId>easy-i18n</artifactId>
<version>1.0</version>
</dependency>

添加Resource Bundle

resources下新增文件夹i18n, 依次添加几个Resource Bundle。具体做法是,在文件夹i18n右键 -> new -> Resource Bundle, 然后选择想要支持的语言。比如美国en_US,简体中文zh_CN

新建MessageService

创建一个Util来处理翻译功能。
com.test.domain.service.IMessageService

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
package com.test.domain.service;
import java.text.MessageFormat;
import java.util.List;
import java.util.Locale;
/**
* The Message translation service
* Created by Ryan Miao on 11/23/17.
*/
public interface IMessageService {
/**
* Get translation by message key.
*
* @param key The message key in the properties
* @return the translated message
*/
String getMessage(String key, Locale locale);
/**
* Get translation by message key and compose it with variables.
* Note that the variable would be injected by {@link MessageFormat}
*
* @param key The message key in the properties
* @param args The variables to inject into the message.
* @return the translated message.
*/
String getMessage(String key, List<String> args, Locale locale);
}

实现类com.test.domain.service.impl.MessageService

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
package com.test.domain.service.impl;
import com.miao.easyi18n.support.ResourceBundleMessageSource;
import com.test.domain.service.IMessageService;
import javax.inject.Inject;
import javax.inject.Singleton;
import java.util.List;
import java.util.Locale;
/**
* Created by Ryan Miao on 11/23/17.
*/
@Singleton
public class MessageService implements IMessageService{
private final ResourceBundleMessageSource messageSource;
@Inject
public MessageService(ResourceBundleMessageSource messageSource) {
this.messageSource = messageSource;
}
@Override
public String getMessage(String key, Locale locale) {
return messageSource.getMessage(key, null, locale);
}
@Override
public String getMessage(String key, List<String> args, Locale locale) {
return messageSource.getMessage(key, args.toArray(), locale);
}
}

在IoC中提供ResourceBundleMessageSource

由于ResourceBundleMessageSource是公共组件,需要单独提取出来,并使用单例模式创建。关于IoC的配置,参阅dropwizard中添加DI

ConfigurationModule中:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
package com.test.domain.ioc.module;
import com.miao.easyi18n.support.ResourceBundleMessageSource;
import com.test.configuration.HelloWorldConfiguration;
import dagger.Module;
import dagger.Provides;
import javax.inject.Singleton;
/**
* Created by Ryan Miao on 11/20/17.
*/
@Module
public class ConfigurationModule {
private final HelloWorldConfiguration configuration;
public ConfigurationModule(HelloWorldConfiguration configuration) {
this.configuration = configuration;
}
@Provides
@Singleton
HelloWorldConfiguration helloWorldConfiguration(){
return configuration;
}
@Singleton
@Provides
ResourceBundleMessageSource resourceBundleMessageSource(){
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
messageSource.addBasenames("i18n/messages", "i18n/messages2", "i18n/otherGroup");
messageSource.setDefaultEncoding("UTF-8");
return messageSource;
}
}

这里,关于Resource Bundle的位置没有单独提出来,后面可以放到HelloWorldConfiguration,提到配置文件中。

测试

在dagger中,接口和实现类的绑定只能通过手动声明。因此,绑定IMessageService

1
2
3
4
5
@Singleton
@Provides
IMessageService messageService(MessageService messageService){
return messageService;
}

创建测试Resource, com.test.domain.resource.LocalResource

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
package com.test.domain.resource;
import com.codahale.metrics.annotation.Timed;
import com.google.common.collect.ImmutableMap;
import com.test.domain.entiry.GithubUser;
import com.test.domain.service.IMessageService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiResponse;
import io.swagger.annotations.ApiResponses;
import javax.inject.Inject;
import javax.validation.Valid;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Pattern;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import java.util.Locale;
import java.util.Map;
/**
* Test localization
* Created by Ryan Miao on 11/23/17.
*/
@Api("/local")
@Path("/local")
@Produces(MediaType.APPLICATION_JSON)
public class LocalResource {
private final IMessageService messageService;
@Inject
public LocalResource(IMessageService messageService) {
this.messageService = messageService;
}
@GET
@Timed
@Path("/{key}")
@ApiOperation(value = "Get github user profile.", notes = "There should be the note.")
@ApiResponses({
@ApiResponse(code = 401, message = "Valid credentials are required to access this resource."),
@ApiResponse(code = 400, message = "Params not valid."),
@ApiResponse(code = 500, message = "Something wrong from the server."),
@ApiResponse(code = 200, message = "Success.", response = GithubUser.class)
})
public Map<String, String> getIndex(
@PathParam("key") final String index,
@HeaderParam("Accept-Language") @Valid
@NotNull(message = "cannot be null.")
@Pattern(regexp = "([a-z]{2}-[A-Z]{2})", message = "pattern should like zh-CN, en-US.")
final String language
) {
final Locale locale = Locale.forLanguageTag(language);
final String message = messageService.getMessage(index, locale);
return ImmutableMap.of(index, message);
}
}

结果

要不要打赏