使用spring-ws开发webservice

spring是一个优雅的框架，将常用的技术粘合在一起。spring-ws相对于其他框架最大的优点是对web服务涉及技术的抽象非常的好，为webservice处理提供统一的模型，而又不限制实现时使用的技术。

发布webservice

发布webservice有以下几个步骤：

1. 编写服务接口定义，包括类型定义，服务方法定义。

2. 实现服务接口定义的方法。

3. 发布服务。

本文已一个订单服务为例

为什么契约优先

开发webservice可以定义java代码，通过框架生产wsdl/xsd内容。也可以采用契约优先方式，先定义wsdl/xsd，然后生成java代码。通过契约优先的方式有以下原因：

1. Object/XML之间的转换。对象与xml转换不能完全的匹配，xsd可以定义对象的限制，比如字符串必须是大写，而java对象没有办法定义限制。

2. java类不是可移植的类型。

3. 环形依赖。如果一个类之间相互依赖，则生成的xml会不停的嵌套。

详情可以参考《Spring Web Services Reference》

编写服务接口定义

定义数据类型，对于请求和反馈，尽量增加一个基础类，这样可以随时增加公共的内容。

xsd文件内容

<?xml version="1.0" encoding="UTF-8"?>
<schema targetNamespace="http://www.nxmax.net/hello"
elementFormDefault="qualified" xmlns="http://www.w3.org/2001/XMLSchema"
xmlns:tns="http://www.nxmax.net/hello">
<complexType name="BaseRespType" abstract="true">
<sequence>
<element name="success" type="boolean" minOccurs="1"
maxOccurs="1" />
<element name="message" type="string" minOccurs="0" />
</sequence>
</complexType>
<complexType name="BaseReqType" abstract="true">
<sequence>
<element name="callerIndentifier" type="string" minOccurs="1" maxOccurs="1"></element>
</sequence>
</complexType>
<element name="CreateOrderReq">
<complexType>
<complexContent>
<extension base="tns:BaseReqType">
<sequence>
<element name="GoodCode" type="string" />
<element name="Amount" type="int" />
<element name="Remarks" type="string" minOccurs="0" />
</sequence>
</extension>
</complexContent>
</complexType>
</element>
<element name="CreateOrderResp">
<complexType>
<complexContent>
<extension base="tns:BaseRespType">
<sequence>
<element name="OrderNum" type="string" minOccurs="1"
maxOccurs="1"></element>
</sequence>
</extension>
</complexContent>
</complexType>
</element>

<element name="InquireReq">
<complexType>
<complexContent>
<extension base="tns:BaseReqType">
<sequence>
<element name="orderNum" type="string" minOccurs="1" maxOccurs="1"></element>
</sequence>
</extension>
</complexContent>
</complexType></element>

<element name="InquireResp">
<complexType>
<complexContent>
<extension base="tns:BaseRespType">
<sequence>
<element name="orderInfo" type="tns:OrderInfoType" minOccurs="0" maxOccurs="1"></element>
</sequence>
</extension>
</complexContent>
</complexType>
</element>

<complexType name="OrderInfoType">
<all>
<element name="orderNum" type="string" minOccurs="1"
maxOccurs="1">
</element>
<element name="date" type="date" minOccurs="1"
maxOccurs="1">
</element>
<element name="time" type="time" minOccurs="1"
maxOccurs="1">
</element>
<element name="goodCode" type="string" minOccurs="1"
maxOccurs="1">
</element>
<element name="remarks" type="string" minOccurs="0" maxOccurs="1"></element>
</all>
</complexType>
</schema>

编写wsdl文件

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<wsdl:definitions name="hello" targetNamespace="http://www.nxmax.net/hello/"
xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="http://www.nxmax.net/hello/"
xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsd1="http://www.nxmax.net/hello" xmlns:mime="http://schemas.xmlsoap.org/wsdl/mime/"
xmlns:http="http://schemas.xmlsoap.org/wsdl/http/">
<wsdl:types>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:import namespace="http://www.nxmax.net/hello"
schemaLocation="hello.xsd">
</xsd:import>
</xsd:schema>
</wsdl:types>
<wsdl:message name="createRequest">
<wsdl:part element="xsd1:CreateOrderReq" name="parameters" />
</wsdl:message>
<wsdl:message name="createResponse">
<wsdl:part element="xsd1:CreateOrderResp" name="parameters" />
</wsdl:message>
<wsdl:message name="inquireRequest">
<wsdl:part name="parameters" element="xsd1:InquireReq"></wsdl:part>
</wsdl:message>
<wsdl:message name="inquireResponse">
<wsdl:part name="parameters" element="xsd1:InquireResp"></wsdl:part>
</wsdl:message>
<wsdl:portType name="Order">
<wsdl:operation name="create">
<wsdl:input message="tns:createRequest" />
<wsdl:output message="tns:createResponse" />
</wsdl:operation>
<wsdl:operation name="inquire">
<wsdl:input message="tns:inquireRequest"></wsdl:input>
<wsdl:output message="tns:inquireResponse"></wsdl:output>
</wsdl:operation>
</wsdl:portType>
<wsdl:binding name="OrderBinding" type="tns:Order">

<soap:binding style="document"
transport="http://schemas.xmlsoap.org/soap/http" />
<wsdl:operation name="create">

<soap:operation
soapAction="http://www.nxmax.net/hello/create" />
<wsdl:input>

<soap:body use="literal" />
</wsdl:input>
<wsdl:output>

<soap:body use="literal" />
</wsdl:output>
</wsdl:operation>
<wsdl:operation name="inquire">
<soap:operation
soapAction="http://www.nxmax.net/hello/inquire" />
<wsdl:input>
<soap:body use="literal" />
</wsdl:input>
<wsdl:output>
<soap:body use="literal" />
</wsdl:output>
</wsdl:operation>
</wsdl:binding>
<wsdl:service name="OrderService">
<wsdl:port binding="tns:OrderBinding" name="OrderPort">
<soap:address location="http://www.example.org/" />
</wsdl:port>
</wsdl:service>
</wsdl:definitions>

spring处理webservice请求原理

一个webservice请求如下，

POST http://localhost:8081/sws/ HTTP/1.1
Content-Type: text/xml;charset=UTF-8
SOAPAction: "http://www.nxmax.net/hello/create"
User-Agent: Jakarta Commons-HttpClient/3.1
Host: localhost:8081
Content-Length: 467

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:hel="http://www.nxmax.net/hello">
<soapenv:Header/>
<soapenv:Body>
<hel:CreateOrderReq>
<hel:callerIndentifier>ewewe</hel:callerIndentifier>
<hel:GoodCode>2323</hel:GoodCode>
<hel:Amount>3</hel:Amount>
<hel:Remarks>2323</hel:Remarks>
<!--Optional:-->
</hel:CreateOrderReq>
</soapenv:Body>
</soapenv:Envelope>

spring接受到请求后通过EndpointMapping获取分发目标。默认spring支持3种分发方式：

1. 通过xml携带的内容确定。soapenv:Body保护了本次请求的内容。通过@PayloadRoot指明，如@PayloadRoot(namespace = “http://www.nxmax.net/hello“, localPart = “CreateOrderReq”)

2. 通过http头中的SOAPAction确定。通过@SoapAction指明，如@SoapAction(“http://www.nxmax.net/hello/create“)

3. 通过WS-Addressing中的Action确定。通过@Action指明，如@Action(“http://globalplatform.org/globaleligibilityinfo/GlobalEligibilityInfo/CheckGlobalEligibilityRequest“)

spring-ws提供灵活处理输入输出的方式，可以手动处理xml，可以通过jaxb将xml转换为对象之后再由应用处理。支持的类型非常广泛，具体可以参考《Spring Web Services Reference》的5.4 Endpoints。

手工处理xml内容

手工处理xml内容需要使用 @PayloadRoot修饰方法，方法的参数类型可以使用org.w3c.dom.Element，示例如下：

package net.nxmax.sws.impl;

import java.io.ByteArrayInputStream;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

// 指定是一个ws入口
@Endpoint
public class XmlEndpoint {
private static final String NAMESPACE_URI = "http://www.nxmax.net/hello";

/** Logger */
private static final Logger LOG = LoggerFactory
.getLogger(XmlEndpoint.class);
private TransformerFactory transFactory = TransformerFactory.newInstance();
private DocumentBuilderFactory cocumentBuilderFactory = DocumentBuilderFactory
.newInstance();

// 使用内容作为分发标识
// @ResponsePayload 指明返回值需要转换
// @RequestPayload 指明是输入的参数
@PayloadRoot(namespace = NAMESPACE_URI, localPart = "CreateOrderReq")
@ResponsePayload
public Element create(@RequestPayload Element req) throws Exception {
LOG.info("REQ XML:{}", e2s(req));
Element rt = getReturn();
LOG.info("RESP XML:{}", e2s(rt));
return rt;
}

private Object e2s(Element req) throws Exception {
Transformer transformer = transFactory.newTransformer();
StringWriter buffer = new StringWriter();
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.transform(new DOMSource(req), new StreamResult(buffer));
String str = buffer.toString();
return str;
}

private Element getReturn() throws Exception {
StringBuilder sb = new StringBuilder();
sb.append("<hel:CreateOrderResp xmlns:hel=\"http://www.nxmax.net/hello\">");
sb.append("<hel:success>true</hel:success>");
sb.append("<hel:message>3232323</hel:message>");
sb.append("<hel:OrderNum>2222222222</hel:OrderNum>");
sb.append("</hel:CreateOrderResp>");

Document x = cocumentBuilderFactory.newDocumentBuilder().parse(
new ByteArrayInputStream(sb.toString().getBytes()));
return x.getDocumentElement();
}
}

函数的参数可以可以包含其他内容，比如MessageContext。比如方法可以定义为

public Element create(@RequestPayload Element req, MessageContext context,
SoapMessage message) throws Exception

MessageContext,SoapMessage是默认启用的，不需要@RequestPayload修饰。

将定义转换为java代码

现在还在使用xml处理webservice，太out了吧。没问题，我们来使用java的标准工具。

java有自带的工具将wsdl/xsd转换为java代码。导入wsdl的是wsimport，导入xsd的是xjc。分别使用以下命令导入。

wsimport -p net.nxmax.sws.def -d ..\java -Xnocompile -verbose -target 2.2 hello.wsdl

xjc -p net.nxmax.sws.def -d ..\java -verbose -no-header hello.xsd

对于spring的调用，xjc就足够了，因为操作可以通过请求确定，完整的wsdl定义就不需要了。

下面是方法的定义

// 下面是使用jaxb，使用soapation的方式
protected ObjectFactory factory = new ObjectFactory();

@SoapAction("http://www.nxmax.net/hello/create")
@ResponsePayload
public CreateOrderResp create(@RequestPayload CreateOrderReq req) {
return factory.createCreateOrderResp();
}

@SoapAction("http://www.nxmax.net/hello/inquire")
@ResponsePayload
public InquireResp inquire(@RequestPayload InquireReq req) {
return factory.createInquireResp();
}

这样就非常方便了。

引用

spring可以使用wsimport生成的定义，但是在spring-ws中使用org.springframework.ws.client.core.WebServiceTemplate功能更强大，灵活。测试代码如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:ws="http://www.springframework.org/schema/web-services" xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/web-services http://www.springframework.org/schema/web-services/web-services.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> 
<bean id="messageFactory" class="org.springframework.ws.soap.saaj.SaajSoapMessageFactory" />

<!-- 定义jaxb对象转换的包名 -->
<bean id="jaxb" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
<property name="contextPath" value="net.nxmax.sws.def"></property>
</bean>

<!-- 定义模板 -->
<bean id="webServiceTemplate" class="org.springframework.ws.client.core.WebServiceTemplate"
p:defaultUri="http://localhost:8081/sws/" p:marshaller-ref="jaxb"
p:unmarshaller-ref="jaxb">
<constructor-arg ref="messageFactory" />
</bean>

</beans>

package net.nxmax.sws.client;

import net.nxmax.sws.def.CreateOrderReq;
import net.nxmax.sws.def.CreateOrderResp;
import net.nxmax.sws.def.ObjectFactory;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
import org.springframework.ws.client.core.WebServiceMessageCallback;
import org.springframework.ws.client.core.WebServiceTemplate;
import org.springframework.ws.soap.client.core.SoapActionCallback;

public class SwsClient {

/** Logger */
private static final Logger LOG = LoggerFactory.getLogger(SwsClient.class);

public static void main(String[] args) {
new SwsClient().go();
}

private void go() {
ObjectFactory factory = new ObjectFactory();
ConfigurableApplicationContext ctx = new GenericXmlApplicationContext(
"classpath:/client.xml");
WebServiceTemplate template = ctx.getBean(WebServiceTemplate.class);

// 指定soapation，与wsdl中的定义一致。如果
WebServiceMessageCallback callback = new SoapActionCallback(
"http://www.nxmax.net/hello/create");
CreateOrderReq req = factory.createCreateOrderReq();

CreateOrderResp resp = (CreateOrderResp) template
.marshalSendAndReceive(req, callback);
LOG.info("Result:{}", resp.isSuccess());
ctx.close();
}

}

示例代码