基于Rest服务实现的RPC

前言：现在RPC成熟的框架已经很多了，比喻Motan和Dubbo，但是今天我这里提供一种基于Rest服务的Rpc。和上一篇连着的http://www.cnblogs.com/LipeiNet/p/5856414.html

1：原理

首先我们要建立一个Rest服务，如果其他应用程序想要获取这个服务的资源就只需要一个URI就可以了。但是由于内部程序的调用我们在通过URI获取json然后在自己处理很不方便，也不是很合适，那么我们就需要利用一个中间层，把访问Rest服务返回的资源重新包装，然后其他工程只需要调用这个rpc工程即可。如下图

2：实现Rest服务

2.1：定义一个用于返回给消费者的实现对象（自己约定的）

public class ResponseBean implements Serializable{private static final long serialVersionUID = -1L;public static final int SUCCESS = 10;public static final int FAILURE = 20;public static final int LOCKED = 30;public static final int EXCEPTION = 40;private int returnCode;//返回给消费者的编码（0表示调用成功,1表示调用失败）private String returnMsg;//返回给消费者错误信息private int dataCount;//用于返回int类型private String returnData;//用户返回jsonprivate Object returnObject;//用于返回对象public ResponseBean() {}public ResponseBean(int returnCode, String returnMsg) {this.returnCode = returnCode;this.returnMsg = returnMsg;}public Object getReturnObject() {return this.returnObject;}public void setReturnObject(Object returnObject) {this.returnObject = returnObject;}public int getDataCount() {return this.dataCount;}public void setDataCount(int dataCount) {this.dataCount = dataCount;}public String getReturnData() {return this.returnData;}public void setReturnData(String returnData) {this.returnData = returnData;}public int getReturnCode() {return this.returnCode;}public void setReturnCode(int returnCode) {this.returnCode = returnCode;}public String getReturnMsg() {return this.returnMsg;}public void setReturnMsg(String returnMsg) {this.returnMsg = returnMsg;}
}

2.2：定一个供外部请求的ApiService

public interface ApiService {String getToken();ResponseBean add(String reqJson);
}

public class ApiServiceImpl implements ApiService {private static final Log log = LogFactory.getLog(ApiServiceImpl.class);@Autowiredprivate UserDao userDao;private String token;//供调用rpc校验使用public String getToken() {return token;}public ResponseBean add(String reqJson) {ResponseBean responseBean = new ResponseBean(ResponseBean.SUCCESS, "调用成功");try {Map map = JsonUtil.g.fromJson(reqJson, HashMap.class);String username = map.get("username").toString();String password = map.get("password").toString();String realname = map.get("realname").toString();Long userroleid =Double.valueOf(map.get("userroleid").toString()).longValue() ;UserBean userBean = new UserBean();userBean.setCreatedate(new Date());userBean.setPassword(password);userBean.setUserroleid(userroleid);userBean.setRealname(realname);userBean.setUsername(username);int count = userDao.add(userBean);responseBean.setReturnData(JsonUtil.g.toJson(count));responseBean.setReturnCode(10);} catch (Exception e) {log.error(e.getStackTrace());responseBean.setReturnCode(11);responseBean.setReturnMsg("服务器异常");}return responseBean;}public void setToken(String token) {this.token = token;//用于设置token（用来验证消费者的token是否是服务器的token）}
}

2.3：定义http请求的入口，需要3个参数token（进行安全认证）、m（请求方法名）、reqJson（请求的参数）

@Controller
@RequestMapping(value = "/api")
public class ApiController {private static final Log log = LogFactory.getLog(ApiController.class);@Autowiredprivate ApiService apiService;/*** 系统对外公开调用方法** @param m       接口方法名* @param reqJson 请求参数* @param token   请求token* @return*/@RequestMapping(value = "/exec", method = RequestMethod.POST)@ResponseBodypublic Object exec(@RequestParam(value = "m", required = true) String m,@RequestParam(value = "reqJson", required = true) String reqJson,@RequestParam(value = "token", required = true) String token) {log.info(String.format("m=%s,reqJson=%s,token=%s", m, reqJson, token));Class c = apiService.getClass();Method method = null;ResponseBean responseBean = null;if (!token.equals(apiService.getToken())) {log.error("token校验失败，token=" + token);responseBean = new ResponseBean(ResponseBean.FAILURE, "校验失败");return responseBean;}try {method = c.getMethod(m, String.class);//利用反射找到对应的方法} catch (Exception e) {log.error("m参数错误,m=" + m + ";req=" + reqJson, e);responseBean = new ResponseBean(ResponseBean.FAILURE, "m参数错误m=" + m);return responseBean;}if (StringUtils.isEmpty(reqJson)) {log.error("reqJson为空");responseBean = new ResponseBean(ResponseBean.FAILURE, "reqJson为空");return responseBean;}try {Object json = method.invoke(apiService, reqJson);return json;} catch (Exception e) {log.error("处理异常,m=" + m + ";req=" + reqJson, e);responseBean = new ResponseBean(ResponseBean.FAILURE, "服务器处理异常");return responseBean;}}
}

通过上面我们就实现了一个供消费者调用的rest服务。

3：RPC对rest服务进行包装

3.1：定义消费者需要的webService

public interface WebService {ResponseBean add(UserBean userBean);
}

实现webService

public class WebserviceImpl implements WebService {private final static Log log = LogFactory.getLog(WebserviceImpl.class);private String url;//供消费者设置的url地址private String token;//供消费者设置的urlpublic void setUrl(String url) {this.url = url;}public void setToken(String token) {this.token = token;}@Overridepublic ResponseBean add(UserBean userBean) {Map<String, String> map = new HashMap();ResponseBean rb = null;map.put("token", token);map.put("reqJson", JsonUtil.g.toJson(userBean));String reqUrl = url + "?m=add";//在这里进行设置你需要访问哪个方法log.debug(reqUrl);try {String str = HttpClientUtil.executeHttpRequestUTF(reqUrl, map);//访问资源获取返回的jsonlog.debug("add return data:" + str);rb = JsonUtil.g.fromJson(str, ResponseBean.class);//对json进行转换log.debug("getPromInfo return Regions data" + reqUrl);return rb;} catch (Exception e) {rb = new ResponseBean();rb.setReturnObject(e);log.debug(e.getStackTrace());return rb;}}
}

然后对rpc进行打包发布，其他应用程序就可以直接使用了。

4：配置

在applicationconfig中加入

<mvc:annotation-driven/><mvc:default-servlet-handler /><mvc:annotation-driven /> 会自动注册DefaultAnnotationHandlerMapping与AnnotationMethodHandlerAdapter 两个bean否则会出现异常

<bean id="ApiService" class="com.lp.rpc.impl.ApiServiceImpl">

    <property name="token" value="41729ff3-3406-4fc5-aeca-04f98892999b"></property></bean>

消费者配置：

<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="webService" class="com.lp.rpc.impl.WebserviceImpl"><property name="url" value="http://192.168.0.101:8088/api/exec"></property><property name="token" value="41729ff3-3406-4fc5-aeca-04f98892999b"></property>
</bean>
</beans>

5：开启一个项目把rpc项目引进调用

public class AppMain {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("application-config.xml");WebService webService = (WebService) context.getBean("webService");UserBean userBean = new UserBean();userBean.setUsername("lisi");userBean.setPassword("123456");userBean.setRealname("李四");userBean.setUserroleid(2);userBean.setCreatedate(new Date());ResponseBean result = webService.add(userBean);if (StringUtils.equals(result.getReturnData().toString(),"1")){System.out.print("添加成功");}}
}

6：总结

以上级别能完成不同项目之间的调用了

优点：简单上手快，可以自己控制，效率也可以。

缺点：安全性低，需要维护url，有时候别人服务反复开启时候会出现调用不到的情况。

源码地址

转载于:https://www.cnblogs.com/LipeiNet/p/5862962.html