WebService框架CXF实战一发布RESTFul服务(七)

JAX-RS概述

JAX-RS是Java提供用于开发RESTful Web服务基于注解(annotation)的API。JAX-RS旨在定义一个统一的规范，使得Java程序员可以使用一套固定的接口来开发REST应用，避免了依赖第三方框架。同时JAX-RS使用POJO编程模型和基于注解的配置并集成JAXB，可以有效缩短REST应用的开发周期。JAX-RS只定义RESTful API，具体实现由第三方提供，如Jersey、Apache CXF等。

JAX-RS包含近五十多个接口、注解和抽象类：

• javax.ws.rs包含用于创建RESTful服务资源的高层次（High-level）接 口和注解。
• javax.ws.rs.core包含用于创建RESTful服务资源的低层次（Low-level）接口和注解。
• javax.ws.rs.ext包含用于扩展JAX-RS API支持类型的APIs。

JAX-RS常用注解：

• @Path：标注资源类或方法的相对路径。
• @GET、@PUT、@POST、@DELETE：标注方法的HTTP请求类型。
• @Produces：标注返回的MIME媒体类型。
• @Consumes：标注可接受请求的MIME媒体类型。
• @PathParam、@QueryParam、@HeaderParam、@CookieParam、@MatrixParam、@FormParam：标注方法的参数来自于HTTP请求的位置。@PathParam来自于URL的路径，@QueryParam来自于URL的查询参数，@HeaderParam来自于HTTP请求的头信息，@CookieParam来自于HTTP请求的Cookie。

服务端

下面用CXF发布一个图书馆RESTFul服务，实现书籍的查询、添加、删除和修改。CXF发布RESTFul服务需要引入cxf-rt-frontend-jaxrs，pom.xml配置如下。

<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>com.rvho</groupId>
    <artifactId>cxfrestserver</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <!-- CXF版本 -->
        <cxf.version>3.1.1</cxf.version>
    </properties>

    <dependencies>
        <!-- CXF -->
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-frontend-jaxrs</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-transports-http</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <!-- 如果在tomcat或者其他servlet容器中发布服务，不需要引用cxf-rt-transports-http-jetty -->
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-transports-http-jetty</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <!-- End CXF -->
    </dependencies>
</project>

书籍XML格式

<Book>
    <author>尼古拉·奥斯特洛夫斯基</author>
    <id>10</id>
    <name>钢铁是怎样炼成的？</name>
    <price>3.0</price>
</Book>

书籍实体类

package com.rvho.rest.server;

import javax.xml.bind.annotation.XmlRootElement;

/**
 * 书籍实体类
 * @author accountwcx@qq.com
 */
@XmlRootElement(name = "Book")
public class Book {
    //id
    private String id;

    //书名
    private String name;
    //作者
    private String author;
    //价格
    private Double price;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public Double getPrice() {
        return price;
    }
    public void setPrice(Double price) {
        this.price = price;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
}

图书馆服务类

package com.rvho.rest.server;

import java.util.HashMap;
import java.util.Map;

import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

/**
 * 图书馆服务
 * @author accountwcx@qq.com
 *
 */
@Path("/library")
@Produces("text/xml")
public class LibraryService {
    private Map<String, Book> books = new HashMap<String, Book>();

    public LibraryService(){
        init();
    }

    /**
     * 获取
     * @param id 索引
     * @return 书
     */
    @GET
    @Path("/books/{id}/")
    public Book getBook(@PathParam("id") String id){
        return books.get(id);
    }

    /**
     * 更新
     * @param book
     * @return
     */
    @PUT
    @Path("/books/")
    public Response updateBook(Book book){
        Response r;
        if(book == null){
            r = Response.noContent().build();
            return r;
        }

        String id = book.getId();
        Book b = books.get(id);
        if(b != null){
            books.put(id, book);
            r = Response.ok(true, MediaType.TEXT_PLAIN).build();
        }else{
            r = Response.notModified().build();
        }

        return r;
    }

    /**
     * 添加
     * @param book
     * @return
     */
    @POST
    @Path("/books/")
    public Response addBook(Book book){
        Response r;
        if(book == null){
            r = Response.notModified().build();
        }else{
            books.put(book.getId(), book);
            r = Response.ok(true, MediaType.TEXT_PLAIN).build();
        }

        return r;
    }

    /**
     * 删除
     * @param book
     * @return
     */
    @DELETE
    @Path("/books/{id}/")
    public Response deleteBook(@PathParam("id") String id){
        Response r;
        Book book = books.get(id);

        if(book == null){
            r = Response.notModified("id不存在").build();
        }else{
            books.remove(id);
            r = Response.ok(book, MediaType.APPLICATION_XML).build();
        }

        return r;
    }


    /**
     * 初始化，在图书馆里加几本书
     */
    private void init(){
        Book book = null;

        book = new Book();      
        book.setAuthor("CSDN");
        book.setId("blog");
        book.setName("如何使用博客");
        book.setPrice(3.0);     
        books.put(book.getId(), book);

        book = new Book();
        book.setAuthor("CSDN");
        book.setId("app");
        book.setName("如何下载CSDN移动客户端");
        book.setPrice(30.0);
        books.put(book.getId(), book);

        book = new Book();
        book.setAuthor("CSDN");
        book.setId("resource");
        book.setName("如何下载CSDN资源");
        book.setPrice(5.0);
        books.put(book.getId(), book);

        book = new Book();
        book.setAuthor("CSDN");
        book.setId("rs");
        book.setName("JAX-RS详解");
        book.setPrice(15.0);
        books.put(book.getId(), book);
    }

}

发布服务

JAXRSServerFactoryBean sf = new JAXRSServerFactoryBean();
sf.setResourceClasses(LibraryService.class);
sf.setResourceProvider(LibraryService.class, new SingletonResourceProvider(new LibraryService()));
sf.setAddress("http://localhost:8280/rest/");
sf.create();

客户端

查询书籍信息，在浏览器中输入http://localhost:8280/rest/library/books/app/

下面用Fiddler模拟POST、DELETE和PUT请求。

添加书籍

<Book>
    <author>鲁迅</author>
    <id>11</id>
    <name>朝花夕拾</name>
    <price>20.0</price>
</Book>

添加返回结果

HTTP/1.1 200 OK
Date: Fri, 31 Jul 2015 06:50:30 GMT
Content-Type: text/plain
Date: Fri, 31 Jul 2015 06:50:30 GMT
Content-Length: 4
Server: Jetty(9.2.10.v20150310)

true

修改书籍

<Book>
    <author>鲁迅</author>
    <id>11</id>
    <name>朝花夕拾</name>
    <price>200.0</price>
</Book>

返回结果

HTTP/1.1 200 OK
Date: Fri, 31 Jul 2015 06:52:24 GMT
Content-Type: text/plain
Date: Fri, 31 Jul 2015 06:52:24 GMT
Content-Length: 4
Server: Jetty(9.2.10.v20150310)

true

删除书籍

返回结果

HTTP/1.1 200 OK
Date: Fri, 31 Jul 2015 06:54:36 GMT
Content-Type: application/xml
Date: Fri, 31 Jul 2015 06:54:36 GMT
Content-Length: 147
Server: Jetty(9.2.10.v20150310)

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><Book><author>鲁迅</author><id>11</id><name>朝花夕拾</name><price>200.0</price></Book>

Tomcat中发布RESTful

CXF在Tomcat中发布服务，需要Spring-Web支持，pom.xml配置如下。

<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>com.rvho</groupId>
    <artifactId>cxfrestserver</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <!-- CXF版本 -->
        <cxf.version>3.1.1</cxf.version>
        <!-- Spring版本 -->
        <spring.version>4.1.7.RELEASE</spring.version>
    </properties>

    <dependencies>
        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- End Spring -->

        <!-- CXF -->
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-frontend-jaxws</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-frontend-jaxrs</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-transports-http</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-transports-http-jetty</artifactId>
            <version>${cxf.version}</version>
        </dependency>
        <!-- End CXF -->
    </dependencies>
</project>

在web.xml中添加CXFServlet

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>cxfrestserver</display-name>

    <!-- Spring配置 -->   
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-context.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <!-- End Spring配置 -->

    <!-- CXF Servlet -->
    <servlet>
        <servlet-name>cxfservlet</servlet-name>
        <servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>cxfservlet</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>
    <!-- End CXF Servlet -->

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

在WEB-INF文件夹下创建cxf-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" 
    xmlns:aop="http://www.springframework.org/schema/aop" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:jaxrs="http://cxf.apache.org/jaxrs" 
    xsi:schemaLocation="
        http://www.springframework.org/schema/aop  http://www.springframework.org/schema/aop/spring-aop.xsd 
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd  
        http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/jaxrs.xsd">

    <bean id="libraryServiceBean" class="com.rvho.rest.server.LibraryService"></bean>
    <jaxrs:server id="libraryServer" address="/">
        <jaxrs:serviceBeans>
            <ref bean="libraryServiceBean"/>
        </jaxrs:serviceBeans>       
    </jaxrs:server>
</beans>

Spring上下文配置

<?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:aop="http://www.springframework.org/schema/aop" 
    xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" 
    xmlns:tx="http://www.springframework.org/schema/tx" 
    xsi:schemaLocation="
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd  
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd  
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

    <!-- <context:annotation-config /> -->

    <!-- 使Spring支持自动检测组件，如注解的Repository、Service、Controller -->
    <context:component-scan base-package="com.rvho" />
</beans>

启动Tomcat，在浏览器中输入http://<地址>/cxfrestserver/rest即可看到服务