Spring MVC实现的RESTful webservice服务器并用Python调用API

大湖之子

下面使用spring MVC+jpa实现一个RESTful webservice服务器，然后用python调用API实现资源的转移，数据库使用mysql，本文仅仅是为了起到一个演示的作用，所以无论是源代码还是配置文件，都只写了有关怎样配置restful服务的部分，关于其他spring的配置问题请参阅相关文档。有什么不当之处，还请不吝赐教！
    第一步，在mysql中建立一个名为spitter的数据库，使用如下的建表语句建立一个用户表spitter，一个发文表spittle：
    CREATE TABLE `spitter` (
    `id` int(11) default NULL,
    `username` char(20) default NULL,
    `password` char(20) default NULL,
    `fullName` char(40) default NULL,
    `email` char(80) default NULL,
    `update_by_email` tinyint(1) default NULL);
    CREATE TABLE `spittle` (
    `id` int(11) default NULL,
    `spittleText` char(200) default NULL,
    `postedTime` datetime default NULL,
    `spitter_id` int(11) default NULL);
    在用户表插入一条记录：
    insert into spitter values('48180', 'john', '19850115', 'john Donkey', 'xglvddz@gmail.com', 1);
    在发文表插入两条记录，表示这个用户发布了两条微博：
    insert into spittle values ('1', 'i live in beijing', now(), '48180');
    insert into spittle values ('2', 'today is sunny', now(), '48180');
    第二步开始编写java代码，怎样建工程，建包在此都省略，
(1)建立spitter控制器：
package com.habuma.spitter.mvc;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.habuma.spitter.domain.Spittle;
import com.habuma.spitter.service.SpitterService;
@Controller
@RequestMapping("/spitters")
public class SpitterController {
private final SpitterService spitterService;
@Autowired
public SpitterController(SpitterService spitterService)
{
this.spitterService = spitterService;
}
//以下方法的RequestMapping注解中的value属性值表示资源的uri为
//servlet上下文+/spitters/{username}/spittles，
//method的值表示客户端请求为GET，
//headers的值表示只有客户端HTTP请求头的Accept值为application/json时才会进入这个方法
@RequestMapping(value = "/{username}/spittles",
method = RequestMethod.GET,
headers = "Accept=application/json")
public @ResponseBody  
List<Spittle> getSpittlesForSpitter(@PathVariable String username)
{
return spitterService.getSpittlesForSpitter(username);
}
}

(2)建立服务层：
package com.habuma.spitter.service;
import java.util.List;
import com.habuma.spitter.domain.Spitter;
import com.habuma.spitter.domain.Spittle;
public interface SpitterService {
List<Spittle> getSpittlesForSpitter(Spitter spitter);
List<Spittle> getSpittlesForSpitter(String username);
Spitter getSpitter(String username);
}
package com.habuma.spitter.service;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import com.habuma.spitter.domain.Spitter;
import com.habuma.spitter.domain.Spittle;
import com.habuma.spitter.persistence.SpitterDao;
@Service("spitterService")
@Transactional(propagation=Propagation.REQUIRED)
public class SpitterServiceImpl implements SpitterService {
public List<Spittle> getSpittlesForSpitter(Spitter spitter) {
return spitterDao.getSpittlesForSpitter(spitter);
}
public List<Spittle> getSpittlesForSpitter(String username) {
Spitter spitter = spitterDao.getSpitterByUsername(username);
return getSpittlesForSpitter(spitter);
}
public Spitter getSpitter(String username) {
return spitterDao.getSpitterByUsername(username);
}
@Autowired
SpitterDao spitterDao;
}

(3)建立Dao：
package com.habuma.spitter.persistence;
import java.util.List;
import com.habuma.spitter.domain.Spitter;
import com.habuma.spitter.domain.Spittle;
public interface SpitterDao {
List<Spittle> getSpittlesForSpitter(Spitter spitter);
Spitter getSpitterByUsername(String username);
}
//<start id="java_contextualJpaDao"/>
package com.habuma.spitter.persistence;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
import com.habuma.spitter.domain.Spitter;
import com.habuma.spitter.domain.Spittle;
@Repository("spitterDao")
@Transactional
public class JpaSpitterDao implements SpitterDao {
private static final String SPITTER_FOR_USERNAME =
"SELECT s FROM Spitter s WHERE s.username = :username";
private static final String SPITTLES_BY_USERNAME =
"SELECT s FROM Spittle s WHERE s.spitter.username = :username";
@PersistenceContext
private EntityManager em;
@SuppressWarnings("unchecked")
public List<Spittle> getSpittlesForSpitter(
Spitter spitter) {
return (List<Spittle>) em.createQuery(SPITTLES_BY_USERNAME).
setParameter("username", spitter.getUsername()).
getResultList();
}

public Spitter getSpitterByUsername(String username) {
return (Spitter) em.createQuery(SPITTER_FOR_USERNAME).
setParameter("username", username).
getSingleResult();
}
}
    第三步，在spitter-servlet.xml中添加下面这两个bean：
    <bean name="spitter/spittles" class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" />
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="mediaTypes">
<map>
<entry key="htm" value="text/html"/>
<entry key="json" value="application/json"/>
</map>
</property>
<property name="defaultViews">
<list>
<bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" />
</list>
</property>
</bean>
其中MappingJacksonJsonView的作用是将java对象映射为JSON格式资源的类，需要在类路径中添加jackson JSON库，ContentNegotiatingViewResolver的作用是根据客户端对返回资源格式的不同需求，配置相应的返回格式，默认的返回JSON格式的资源
    第四步，在eclipse的pyDev视图下使用python调用这个api，显示用户john所发的所有微博，代码如下：
#!/bin/env python
import httplib
import os, sys
import traceback
# Web Services API Utilities
from wsautils import *
GET  = 'GET'
POST = 'POST'
DELETE = 'DELETE'
PUT = 'PUT'
def executeRequest(method, uri, body=None):
connection = httplib.HTTPConnection( 'localhost', 8090 )
requestHeaders={'Content-Type': 'application/json', 'Accept': 'application/json'}
connection.request( method, uri, body, requestHeaders )
response = connection.getresponse()
result   = Response( response.status, response.reason, response.getheaders(), response.read(), None )
return result
#get a user's spittle(s)
result = executeRequest(GET, '/Spitter/spitters/john/spittles')
print result
这个例子中，在tomcat里设置服务器接受http请求的端口为8090，httplib是python内置的用于http调用的模块，wsautils是我自己的module，这里就引用了其中的Response类，来封装一个http response，大家也可以根据需要自己也一个这样的类，下面是运行结果：
Response Status  : 200
Response Reason  : OK
Response Headers : {'transfer-encoding': 'chunked', 'date': 'Fri, 04 Apr 2014 05:31:19 GMT', 'content-type': 'application/json', 'server': 'Apache-Coyote/1.1'}
Response Body    : [
{
  "text":"i live in beijing",
  "when":1393870571000,
  "id":1,
  "spitter":{
   "username":"john",
   "updateByEmail":true,
   "email":"xglvddz@gmail.com",
   "fullName":"john Donkey",
   "password":"19850115",
   "id":48180
  }
},
{
  "text":"today is sunny",
  "when":1396587047000,
  "id":2,
  "spitter":{
   "username":"john",
   "updateByEmail":true,
   "email":"xglvddz@gmail.com",
   "fullName":"john Donkey",
   "password":"19850115",
   "id":48180
  }
}
]