Web Services是由企业发布的完成其特定商务需求的在线应用服务，其他公司或应用软件能够通过Internet来访问并使用这项在线服务。

Web Service的关键技术和规则:

1.XML:描述数据的标准方法.

2.SOAP：表示信息交换的协议（简单对象访问协议）.

3.WSDL：Web服务描述语言.

4.UDDI:通用描述、发现与集成，他是一种独立于平台，基于XML语言的用于在互联网上描述商务的协议。

一、利用JDK web服务api实现，这里使用基于SOAP message的Web Service：

1.首先创建一个Web Services项目

2.创建一个SayHello.java类，执行类，生成wsdl文件

@WebService
public class SayHello {

    public String hello(String message){  
        return "Hello ," + message;  
    }  
      
    public static void main(String[] args) {  
        //create and publish an endPoint  
        SayHello hello = new SayHello();  
        Endpoint.publish("http://localhost:8080/hello", hello);  
    }  
}

可通过http://localhost:8080/hello？wsdl查看

三、执行dos命令执行：wsimport -p wsp.service -keep http://localhost:8080/hello?wsdl，生成文件取.java文件到项目中

　　生成文件：

粘贴到项目中的java文件，用于调用

四、编写调用类进行调用，注意：调用的服务是生成的，不是自己写的

package wsp.main;

import wsp.service.SayHello;注意这儿
import wsp.service.SayHelloService;

public class Execute {

    public static void main(String[] args) {
        SayHelloService shs = new SayHelloService();
        SayHello sh = shs.getSayHelloPort();
        System.out.println(sh.hello("TOM"));
    }
}

中间出现的错误，原因可能是，包不对，注意生成java代码的时候生成的包要和存到项目中的包名一样，避免修改包名和不必要的麻烦

Exception in thread "main" javax.xml.ws.WebServiceException: Unable to create JAXBContext
    at com.sun.xml.internal.ws.model.AbstractSEIModelImpl.createJAXBContext(AbstractSEIModelImpl.java:156)
    at com.sun.xml.internal.ws.model.AbstractSEIModelImpl.postProcess(AbstractSEIModelImpl.java:84)
    at com.sun.xml.internal.ws.model.RuntimeModeler.buildRuntimeModel(RuntimeModeler.java:235)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.createSEIPortInfo(WSServiceDelegate.java:652)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.addSEI(WSServiceDelegate.java:640)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.getPort(WSServiceDelegate.java:332)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.getPort(WSServiceDelegate.java:315)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.getPort(WSServiceDelegate.java:297)
    at javax.xml.ws.Service.getPort(Service.java:119)
    at wsp.service.SayHelloService.getSayHelloPort(SayHelloService.java:72)
    at wsp.main.Execute.main(Execute.java:10)
Caused by: java.security.PrivilegedActionException: com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions
Two classes have the same XML type name "{http://webservice.wsp/}hello". Use @XmlType.name and @XmlType.namespace to assign different names to them.
    this problem is related to the following location:
        at wsp.service.Hello
        at public javax.xml.bind.JAXBElement wsp.service.ObjectFactory.createHello(wsp.service.Hello)
        at wsp.service.ObjectFactory
    this problem is related to the following location:
        at wsp.webservice.Hello
Two classes have the same XML type name "{http://webservice.wsp/}helloResponse". Use @XmlType.name and @XmlType.namespace to assign different names to them.
    this problem is related to the following location:
        at wsp.service.HelloResponse
        at public wsp.service.HelloResponse wsp.service.ObjectFactory.createHelloResponse()
        at wsp.service.ObjectFactory
    this problem is related to the following location:
        at wsp.webservice.HelloResponse

    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.xml.internal.ws.model.AbstractSEIModelImpl.createJAXBContext(AbstractSEIModelImpl.java:143)
    ... 10 more
Caused by: com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions
Two classes have the same XML type name "{http://webservice.wsp/}hello". Use @XmlType.name and @XmlType.namespace to assign different names to them.
    this problem is related to the following location:
        at wsp.service.Hello
        at public javax.xml.bind.JAXBElement wsp.service.ObjectFactory.createHello(wsp.service.Hello)
        at wsp.service.ObjectFactory
    this problem is related to the following location:
        at wsp.webservice.Hello
Two classes have the same XML type name "{http://webservice.wsp/}helloResponse". Use @XmlType.name and @XmlType.namespace to assign different names to them.
    this problem is related to the following location:
        at wsp.service.HelloResponse
        at public wsp.service.HelloResponse wsp.service.ObjectFactory.createHelloResponse()
        at wsp.service.ObjectFactory
    this problem is related to the following location:
        at wsp.webservice.HelloResponse

    at com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException$Builder.check(IllegalAnnotationsException.java:91)
    at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.getTypeInfoSet(JAXBContextImpl.java:451)
    at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:283)
    at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:126)
    at com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl$JAXBContextBuilder.build(JAXBContextImpl.java:1142)
    at com.sun.xml.internal.bind.v2.ContextFactory.createContext(ContextFactory.java:173)
    at com.sun.xml.internal.bind.api.JAXBRIContext.newInstance(JAXBRIContext.java:96)
    at com.sun.xml.internal.ws.developer.JAXBContextFactory$1.createJAXBContext(JAXBContextFactory.java:98)
    at com.sun.xml.internal.ws.model.AbstractSEIModelImpl$1.run(AbstractSEIModelImpl.java:151)
    at com.sun.xml.internal.ws.model.AbstractSEIModelImpl$1.run(AbstractSEIModelImpl.java:143)
    ... 12 more

webservice的简单运用