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java如何写接口给别人调用的示例代码

2020年02月13日 编程语言 ⁄ 共 11825字 ⁄ 字号 评论关闭

计算机语言分类有很多,如C、C++、C#、Java、Php、Python等等,她们有各自的特性及擅长的领域,但她们各自又不是全能的。在一个稍微大型一点的项目都会用到多种语言共同完成,那么这些编程语言如何进行通信呢。什么意思呢,就是比如说我Java写的一个方法,其他编程语言要怎么去调用呢?这就是本文要探讨的问题了。

一般来说,方法层面的编程语言通信用的是网络接口形式,只暴露出形参和结果供别人调用。接口一般分为接口定义者和接口调用者,定义者可以规定接收参数的类型及返回形式,而接口定义者则只能完全按照接口定义者规定的参数进行访问。就叫是我们所说的webService(网络服务)。

以前的做法是利用XML作接口格式定义,然后通过Http做通讯和请求,如大名鼎鼎的SOAP,其实现在也是的,只不过现在流行RestFul风格的Rest接口形式,但用的还是XML+HTTP,那这两者有啥区别呢?最大的区别就是SOAP返回的主要是XML格式,有时还需要附带一些辅助文件,而Rest则还可以返回JSON类型的字符串,减少了很多繁乱的XML标签。本文就以Java为例,用她写一个接口,并让其他人去调用,以此来简单展示接口调用是怎么样一个过程。

步骤:

1、本机装有Java JDK运行环境及编程IDE(如Myeclipse)

2、建立一个maven项目,用以下载jar包,项目结构如下:

3 pom.xml文件内容如下:

<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>ws</groupId> <artifactId>restful</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>restful-server</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <jersey.version>2.6</jersey.version> <jersey-spring.version>2.23.1</jersey-spring.version> <spring.version>4.2.7.RELEASE</spring.version> <servlet-api-version>3.1.0</servlet-api-version> <logback.version>1.1.1</logback.version> <jcloverslf4j.version>1.7.6</jcloverslf4j.version> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.glassfish.jersey.ext</groupId> <artifactId>jersey-spring3</artifactId> <version>${jersey-spring.version}</version> <exclusions> <exclusion> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> </exclusion> <exclusion> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> </exclusion> <exclusion> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.glassfish.jersey.containers</groupId> <artifactId>jersey-container-servlet</artifactId> <version>${jersey-spring.version}</version> </dependency> <dependency> <groupId>org.glassfish.jersey.containers</groupId> <artifactId>jersey-container-servlet-core</artifactId> <version>${jersey-spring.version}</version> </dependency> <dependency> <groupId>org.glassfish.jersey.media</groupId> <artifactId>jersey-media-json-jackson</artifactId> <version>${jersey.version}</version> </dependency> <dependency> <groupId>org.glassfish.jersey.media</groupId> <artifactId>jersey-media-multipart</artifactId> <version>${jersey.version}</version> </dependency> <dependency> <groupId>org.glassfish.jersey.ext</groupId> <artifactId>jersey-entity-filtering</artifactId> <version>${jersey.version}</version> </dependency> <!-- Spring4.2 dependencies --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</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-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>${servlet-api-version}</version> <scope>provided</scope> </dependency> <!-- Logback dependencies --> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>${logback.version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>jcl-over-slf4j</artifactId> <version>${jcloverslf4j.version}</version> </dependency> </dependencies> <build> <finalName>restful</finalName> </build></project>

4 applicationContext.xml内容如下:

<?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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd"> <context:component-scan base-package="com.kendy.*"></context:component-scan></beans>

5 web.xml则主要配置采用的容器、日志管理及拦截器,拦截器可以实现到达请求郑涛之前进行身份认证,踢除没有访问资格的请求,而rest项目一般是用Jersey容器。配置如下:(kendy只是我的英文名,你们可以自己定义路径)

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:javaee="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <servlet> <servlet-name>jersey-serlvet</servlet-name> <servlet-class> org.glassfish.jersey.servlet.ServletContainer </servlet-class> <init-param> <param-name>javax.ws.rs.Application</param-name> <param-value>com.kendy.filter.RestJaxRsApplication</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>jersey-serlvet</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping></web-app>

6 拦截器如下:

import java.io.IOException;import java.io.InputStream;import java.util.List;import java.util.Map.Entry; import javax.ws.rs.WebApplicationException;import javax.ws.rs.container.ContainerRequestContext;import javax.ws.rs.container.ContainerRequestFilter;import javax.ws.rs.core.MultivaluedMap;import javax.ws.rs.core.Response.Status;import javax.ws.rs.ext.Provider; /** * 拦截请求 */@Providerpublic class MyFilter implements ContainerRequestFilter { @Override public void filter(ContainerRequestContext context) throws IOException { //打印出所有请求头 MultivaluedMap<String, String> map = context.getHeaders(); for(Entry<String, List<String>> entry : map.entrySet()){ String key = entry.getKey(); List<String> valueList = entry.getValue(); String values = valueList.toString(); System.out.println(key + ":"+values.substring(1,values.length()-1)); }

7 注册Jersey容器所要管理的类

import org.codehaus.jackson.jaxrs.JacksonJsonProvider;import org.glassfish.jersey.server.ResourceConfig; import com.kendy.restful.AccountManager;import com.kendy.restful.AuthorityManager;import com.kendy.restful.CardManager;import com.kendy.restful.DeviceManager;import com.kendy.restful.UserResource; /** * ${DESCRIPTION} */public class RestJaxRsApplication extends ResourceConfig { /** * Register JAX-RS application components. */ public RestJaxRsApplication() { //服务类所在的包路径 packages("com.kendy.*"); // register application resources this.register(YouClass.class); // register filters this.register(MyFilter.class); //this.register(RequestContextFilter.class); register(JacksonJsonProvider.class); //register(MultiPartFeature.class); }}

8 接口定义(Restful风格)

package com.kendy.restful; import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Date;import java.util.HashMap;import java.util.List;import java.util.Map; import javax.ws.rs.Consumes;import javax.ws.rs.POST;import javax.ws.rs.Path;import javax.ws.rs.Produces;import javax.ws.rs.core.MediaType; import org.springframework.stereotype.Component; @Component@Path("/CardManager")public class CardManager { private SimpleDateFormat sdf =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); @POST @Path("size") @Consumes(MediaType.APPLICATION_JSON) @Produces(MediaType.APPLICATION_JSON) public Map<String,Object> size(){ Map<String,Object> map = new HashMap<>(); //do something here map.put("Size", 1024); return map; } @POST @Path("getDetail") @Consumes(MediaType.APPLICATION_JSON) @Produces(MediaType.APPLICATION_JSON) public Map<String,List<Map<String,Object>>> getDetail(){ Map<String,List<Map<String,Object>>> map = new HashMap<>(); //do something here List<Map<String,Object>> list = new ArrayList<>(); Map<String,Object> subMap = new HashMap<>(); subMap.put("UUID", 10086); subMap.put("CardID", 10081); subMap.put("StartTime", sdf.format(new Date())); subMap.put("EndTime", sdf.format(new Date())); list.add(subMap); map.put("Card", list); return map; }}

9 调用接口,有多种方式,本文用HttpClient

/** * 发送 post请求webService接口 * @param url 访问的接口地址 * @param account 用户名 * @param code 密码 * @param param 查询参数 * @return HttpResponse 该类包含请求方法的态码及返回的数据 */ public static HttpResponse post(String url,String account,String code,Map<String,Object> param) { //创建HttpClient实例及Post方法 HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost(url); //对用户密码MD5加密code = getMD5(code);//添加相关请求头,依情况而定httppost.setHeader("Authorization","WSSE profile=\"UsernameToken\""); httppost.setHeader("X-WSSE","UsernameToken Username=\""+account+"\",PasswordDigest=\""+code+"\""); httppost.addHeader("Content-type","application/json; charset=utf-8"); httppost.setHeader("Accept", "application/json"); httppost.setHeader("Connection","keep-alive"); httppost.setHeader("Accept-Encoding","gzip"); httppost.setHeader("Accept-Language", "zh-CN,en,*"); httppost.setHeader("User-Agent","Mozilla/5.0"); //传递请求参数String paramJsonStr = JSON.toJSONString(param);if(param != null)httppost.setEntity(new StringEntity(paramJsonStr, Charset.forName("UTF-8"))); HttpResponse response = null;try { //执行post请求 response = httpclient.execute(httppost); } catch (Exception e) { e.printStackTrace(); } return response; }

10 返回接口

11 最后通过Map、List和Json工具对返回来的字面量进行各种处理。

/** * 将从接口返回的JSON数据转换为实体集合等待插入数据表 * 实体 IgmAccessControlChannelModel --> IGM_ACCESSCONTROL_CHANNEL * IgmStationDoorModel --> IGM_STATION_DOOR */@SuppressWarnings({ "unchecked", "rawtypes" })private Map<String,Object> getDeviceEntityList(String data){Map<String,Object> totalMap = new HashMap<>();//把以下三个结果放到totalMap里返回List<IgmAccessControlChannelModel> accessControlList = new ArrayList<>();List<IgmStationDoorModel> doorList = new ArrayList<>();List<String> deviceIds = new ArrayList<>();IgmAccessControlChannelModel accessControlModel = null;IgmStationDoorModel stationDoorModel = null;Map map = JSON.parseObject(data, Map.class);map = (Map<String,List<Map<String,Object>>>)map;List<Map<String,Object>> deviceList = (List<Map<String, Object>>) map.get("Device");for(Map<String,Object> deviceMap : deviceList){String deviceId = (String)(deviceMap.get("DeviceID")+"");Object channels = deviceMap.get("Channels");List<Map<String,Object>> channelList = (List<Map<String,Object>>)channels;String id = ""; //用于设置igmaccessControlchannel表和igmstationDoor表的stationDoorid//判断该门禁设备ID在本平台是否匹配boolean isMatched = isDeviceIdMatched(deviceId);if(isMatched){for(Map<String,Object> chnnelMap : channelList){accessControlModel = new IgmAccessControlChannelModel();stationDoorModel = new IgmStationDoorModel();for(Map.Entry<String, Object> entry : chnnelMap.entrySet()){String key = entry.getKey().trim();String value = "";if(key.equals("Channel")){value =(Integer)entry.getValue()+"";}else{value = (String)entry.getValue();}switch(key){case "Channel":accessControlModel.setCommandCode(Integer.parseInt(value));accessControlModel.setControlChannelName("控制通道"+value);stationDoorModel.setDoorCode(value);break;case "Description":stationDoorModel.setStationDoorName(value);break;default: break;}}id = UUID.randomUUID().toString();accessControlModel.setAccessControlChannelId(UUID.randomUUID().toString());accessControlModel.setDeviceId(deviceId);accessControlModel.setStationDoorId(id);stationDoorModel.setStationDoorId(id);stationDoorModel.setDeviceId(deviceId);stationDoorModel.setRemark("指纹门禁");accessControlList.add(accessControlModel);doorList.add(stationDoorModel);}deviceIds.add(deviceId);}else{//deviceId不匹配的跳过}}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持我们。

本文标题: java如何写接口给别人调用的示例代码

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