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', '[email protected]', 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":"[email protected]",
"fullName":"john Donkey",
"password":"19850115",
"id":48180
}
},
{
"text":"today is sunny",
"when":1396587047000,
"id":2,
"spitter":{
"username":"john",
"updateByEmail":true,
"email":"[email protected]",
"fullName":"john Donkey",
"password":"19850115",
"id":48180
}
}
]