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30分钟学会使用Spring Web Services基础开发
时隔一年终于又推出了一篇30分钟系列,上一篇《30分钟学会反向Ajax》是2016年7月的事情了。时光荏苒,岁月穿梭。虽然一直还在从事Java方面的开发工作,但是私下其实更喜欢使用C++。不过今天,我们要再次回归到Java的主题,来谈一谈如何使用——Spring Web Services框架。
Spring Web Services(下简称ws)本质上是基于SpringBoot的项目,因此如果有对SpringBoot不太了解的同学,回头再来看比较合适。
ws分为server端与client端两个部分,本文旨在介绍框架搭建的流程与重点。
一、ws.server端搭建
建立Server的关键是首先建立xsd文件。xsd文件是xml文件的定义与基础,你希望别人如何访问与获取你的数据都需要在xsd文件中说明。
countries.xsd
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:tns="http://learnhow.org/ws/schema" targetNamespace="http://learnhow.org/ws/schema"
elementFormDefault="qualified">
<xs:element name="getCountryRequest">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="getCountryResponse">
<xs:complexType>
<xs:sequence>
<xs:element name="country" type="tns:country" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:complexType name="country">
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="population" type="xs:int" />
<xs:element name="capital" type="xs:string" />
<xs:element name="currency" type="tns:currency" />
<xs:element name="language" type="tns:language" />
</xs:sequence>
</xs:complexType>
<xs:simpleType name="currency">
<xs:restriction base="xs:string">
<xs:enumeration value="GBP" />
<xs:enumeration value="EUR" />
<xs:enumeration value="PLN" />
</xs:restriction>
</xs:simpleType>
<xs:complexType name="language">
<xs:sequence>
<xs:element name="name" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:schema>
users.xsd
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:tns="http://learnhow.org/ws/schema" targetNamespace="http://learnhow.org/ws/schema"
elementFormDefault="qualified">
<xs:element name="getUserRequest">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="getUserResponse">
<xs:complexType>
<xs:sequence>
<xs:element name="user" type="tns:user" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:complexType name="user">
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="gender" type="tns:gender" />
<xs:element name="age" type="xs:int" />
<xs:element name="address" type="xs:string" />
</xs:sequence>
</xs:complexType>
<xs:simpleType name="gender">
<xs:restriction base="xs:string">
<xs:enumeration value="MALE" />
<xs:enumeration value="FEMALE" />
</xs:restriction>
</xs:simpleType>
</xs:schema> |
这两个文件默认请存放于 src/main/resources 目录下,如下图所示:
建立完成以后我们可以着手编写pom.xml文件,即建立工程依赖。
<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>org.learnhow</groupId>
<artifactId>ws.server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>ws.server</name>
<url>http://maven.apache.org</url>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
</parent>
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web-services</artifactId>
</dependency>
<dependency>
<groupId>wsdl4j</groupId>
<artifactId>wsdl4j</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jaxb2-maven-plugin</artifactId>
<version>1.6</version>
<executions>
<execution>
<id>xjc</id>
<goals>
<goal>xjc</goal>
</goals>
</execution>
</executions>
<configuration>
<schemaDirectory>${project.basedir}/src/main/resources/</schemaDirectory>
<outputDirectory>${project.basedir}/src/main/java</outputDirectory>
<clearOutputDir>false</clearOutputDir>
</configuration>
</plugin>
</plugins>
</build>
</project> |
重点是最后的一项maven plugin,它会读取resources目录下的xsd文件并在 src/main/java 目录下建立.java文件。需要注意的是代码的package路径是通过xsd的targetNamespace事先指定的。
代码文件被maven创建完成以后代表第一段工作顺利完成。下面我们需要人工编写Endpoint类,即建立对外访问的服务接口。通常你提供了几分xsd文件就应该创建几个Endpoint类。Endpoint本质上是接收一个request,然后经过你的业务逻辑再返回一个response。与传统意义上的浏览器不同,后者通常传输json字符串,而前者则是xml。
CountryEndpoint
package org.learnhow.ws.server;
import org.learnhow.ws.schema.GetCountryRequest;
import org.learnhow.ws.schema.GetCountryResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ws.server.endpoint.annotation.Endpoint;
import org.springframework.ws.server.endpoint.annotation.PayloadRoot;
import org.springframework.ws.server.endpoint.annotation.RequestPayload;
import org.springframework.ws.server.endpoint.annotation.ResponsePayload;
@Endpoint
public class CountryEndpoint {
private static final String NAMESPACE_URI = "http://learnhow.org/ws/schema";
@Autowired
private CountryRepository countryRepository;
@PayloadRoot(namespace = NAMESPACE_URI, localPart = "getCountryRequest")
@ResponsePayload
public GetCountryResponse getCountry(@RequestPayload GetCountryRequest request) {
GetCountryResponse response = new GetCountryResponse();
response.setCountry(countryRepository.findCountry(request.getName()));
return response;
}
} |
UserEndpoint
package org.learnhow.ws.server;
import org.learnhow.ws.schema.GetUserRequest;
import org.learnhow.ws.schema.GetUserResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ws.server.endpoint.annotation.Endpoint;
import org.springframework.ws.server.endpoint.annotation.PayloadRoot;
import org.springframework.ws.server.endpoint.annotation.RequestPayload;
import org.springframework.ws.server.endpoint.annotation.ResponsePayload;
@Endpoint
public class UserEndpoint {
private static final String NAMESPACE_URI = "http://learnhow.org/ws/schema";
@Autowired
private UserRepository userRepository;
@PayloadRoot(namespace = NAMESPACE_URI, localPart = "getUserRequest")
@ResponsePayload
public GetUserResponse getUser(@RequestPayload GetUserRequest request) {
GetUserResponse response = new GetUserResponse();
response.setUser(userRepository.findUser(request.getName()));
return response;
}
} |
很显然你的业务逻辑应该封装在CountryRepository和UserRepository对象里。接下来创建CountryRepository对象。
CountryRepository
package org.learnhow.ws.server;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.PostConstruct;
import org.learnhow.ws.schema.Country;
import org.learnhow.ws.schema.Currency;
import org.learnhow.ws.schema.Language;
import org.springframework.stereotype.Component;
@Component
public class CountryRepository {
private static final Map<String, Country> countries = new HashMap<>();
@PostConstruct
public void initData() {
Country spain = new Country();
spain.setName("Spain");
spain.setCapital("Madrid");
spain.setCurrency(Currency.EUR);
spain.setPopulation(46704314);
Language spanish = new Language();
spanish.setName("spanish");
spain.setLanguage(spanish);
Country poland = new Country();
poland.setName("Poland");
poland.setCapital("Warsaw");
poland.setCurrency(Currency.PLN);
poland.setPopulation(38186860);
Language polish = new Language();
polish.setName("polish");
poland.setLanguage(polish);
Country uk = new Country();
uk.setName("United Kingdom");
uk.setCapital("London");
uk.setCurrency(Currency.GBP);
uk.setPopulation(63705000);
Language english = new Language();
english.setName("english");
uk.setLanguage(english);
countries.put(spain.getName(), spain);
countries.put(poland.getName(), poland);
countries.put(uk.getName(), uk);
}
public Country findCountry(String name) {
return countries.get(name);
}
} |
UserRepository(略)
最后是编写configuration,它是整个框架调用的核心。
package org.learnhow.ws.server;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.ws.config.annotation.EnableWs;
import org.springframework.ws.config.annotation.WsConfigurerAdapter;
import org.springframework.ws.transport.http.MessageDispatcherServlet;
import org.springframework.ws.wsdl.wsdl11.DefaultWsdl11Definition;
import org.springframework.xml.xsd.SimpleXsdSchema;
import org.springframework.xml.xsd.XsdSchema;
@EnableWs
@Configuration
public class WebServiceConfig extends WsConfigurerAdapter {
@Bean
public ServletRegistrationBean messageDispatcherServlet(ApplicationContext applicationContext) {
MessageDispatcherServlet servlet = new MessageDispatcherServlet();
servlet.setApplicationContext(applicationContext);
servlet.setTransformWsdlLocations(true);
return new ServletRegistrationBean(servlet, "/ws/*");
}
@Bean(name = "countries")
public DefaultWsdl11Definition defaultWsdl11DefinitionCountry() {
DefaultWsdl11Definition wsdl11Definition = new DefaultWsdl11Definition();
wsdl11Definition.setPortTypeName("CountriesPort");
wsdl11Definition.setLocationUri("/ws");
wsdl11Definition.setTargetNamespace("http://learnhow.org/ws/schema");
wsdl11Definition.setSchema(countriesSchema());
return wsdl11Definition;
}
@Bean(name = "users")
public DefaultWsdl11Definition defaultWsdl11DefinitionUser() {
DefaultWsdl11Definition wsdl11Definition = new DefaultWsdl11Definition();
wsdl11Definition.setPortTypeName("CountriesPort");
wsdl11Definition.setLocationUri("/ws");
wsdl11Definition.setTargetNamespace("http://learnhow.org/ws/schema");
wsdl11Definition.setSchema(usersSchema());
return wsdl11Definition;
}
@Bean
public XsdSchema countriesSchema() {
return new SimpleXsdSchema(new ClassPathResource("countries.xsd"));
}
@Bean
public XsdSchema usersSchema() {
return new SimpleXsdSchema(new ClassPathResource("users.xsd"));
}
} |
最后一步:编写启动项Application
package org.learnhow.ws;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
} |
完成的目录结构如下:
二、测试
启动application,打开浏览器访问:http://localhost:8080/ws/countries.wsdl与http://localhost:8080/ws/users.wsdl 如果页面分别展示了两份xml文件代表服务器已经可以正常运行了。也可以用SoapUI Pro进一步测试数据的读取和发送是否正常。
三、ws.client端搭建
如果说server端是通过xsd产生java与WSDL的过程那么client端就恰恰相反。我们还是使用maven工具通过服务器暴露在外的wsdl文件建立java对象。首先编辑pom.xml文件配置依赖和wsdl访问路径。
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.learnhow</groupId>
<artifactId>ws.client</artifactId>
<packaging>jar</packaging>
<version>0.0.1-SNAPSHOT</version>
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.ws</groupId>
<artifactId>spring-ws-core</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.jvnet.jaxb2.maven2</groupId>
<artifactId>maven-jaxb2-plugin</artifactId>
<version>0.13.2</version>
<executions>
<execution>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
<configuration>
<schemaLanguage>WSDL</schemaLanguage>
<generatePackage>ws.wsdl</generatePackage>
<schemas>
<schema>
<url>http://localhost:8080/ws/countries.wsdl</url>
</schema>
<schema>
<url>http://localhost:8080/ws/users.wsdl</url>
</schema>
</schemas>
</configuration>
</plugin>
</plugins>
</build>
</project> |
这里要注意,如果此时你已经将server的进程停止,也就是wsdl无法访问,pom.xml文件会报错。看上去大概会像这样:
正常情况下maven会自动帮你在target目录下建立java对象,目录结构如下:
如果你发现无法正常建立java对象,请首先检查以下两点:
maven引入的依赖是否完整:国内的网络环境不是很好,有时候通过maven搭建环境经常会在运行时报出各种莫名其妙的错误。其中绝大多数其实都是由于依赖引入不完整造成的。此时你可能需要对Maven Dependencies目录下的jar包逐一检查。
maven结构错误:maven的版本很多,不同的版本间可能在元素的结构定义上有所差距。如果在<plugins>节点报错可以考虑在外层再包一层<pluginManagement>节点。具体原因我也没有深究,只能说“有时管用”,如果你对maven有深入的了解也希望告诉我。
如果以上环境你进行的都很顺利,那么恭喜你80%的工作已经完成了。
下面是编写client客户端代码:
package org.learnhow.ws.client;
import org.springframework.ws.client.core.support.WebServiceGatewaySupport;
import org.springframework.ws.soap.client.core.SoapActionCallback;
import ws.wsdl.GetCountryRequest;
import ws.wsdl.GetCountryResponse;
public class CountryClient extends WebServiceGatewaySupport {
public static final String URI = "http://localhost:8080/ws";
public static final String SOAPACTION = "http://learnhow.org/ws/schema/getUserRequest";
public GetCountryResponse getCountry(String countryName) {
GetCountryRequest request = new GetCountryRequest();
request.setName(countryName);
GetCountryResponse response = (GetCountryResponse) getWebServiceTemplate().marshalSendAndReceive(URI, request,
new SoapActionCallback(SOAPACTION));
return response;
}
} |
UserClient(略)
然后依然是创建configuration供框架调用
package org.learnhow.ws.client;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.oxm.jaxb.Jaxb2Marshaller;
@Configuration
public class AppConfiguration {
@Bean
public Jaxb2Marshaller marshaller() {
Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
marshaller.setContextPath("ws.wsdl");
return marshaller;
}
@Bean("country")
public CountryClient counrtyClient(Jaxb2Marshaller marshaller) {
CountryClient client = new CountryClient();
client.setDefaultUri(CountryClient.URI);
client.setMarshaller(marshaller);
client.setUnmarshaller(marshaller);
return client;
}
@Bean("user")
public UserClient userClient(Jaxb2Marshaller marshaller) {
UserClient client = new UserClient();
client.setDefaultUri(UserClient.URI);
client.setMarshaller(marshaller);
client.setUnmarshaller(marshaller);
return client;
}
} |
最后是编写Application启动项
package org.learnhow.ws;
import org.learnhow.ws.client.CountryClient;
import org.learnhow.ws.client.UserClient;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import ws.wsdl.GetCountryResponse;
import ws.wsdl.GetUserResponse;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Bean
CommandLineRunner lookup(CountryClient client) {
return args -> {
String countryName = "Spain";
if (args.length > 0) {
countryName = args[0];
}
GetCountryResponse response = client.getCountry(countryName);
System.out.println("response: " + response.getCountry().getName());
};
}
} |
运行application,如果你能看到控制台有 "response: Spain" 打出代表数据已经能够正常获取。
后记:
本文的代码逻辑主要参考了Spring Web Services官网文档。另外WebService除了通过Spring还有多种实现手段,感兴趣的同学可以看看如何使用wsimport工具以及Tomcat发布WebService的例子。这里不再赘述。
程序猿的技术大观园:www.javathinker.net
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