Apache HttpClient调用Spring3 MVC Restful Web API演示
使用HttpRequest提交数据与HttpResponse响应客户端都是支持json数据格式，实现在HTTP Client端调用Spring3 MVC Restful API例子。需要用到的maven依赖如下：
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.1</version> </dependency> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.5</version> </dependency>
添加了maven依赖之后，就可以先完成HttpClient演示程序，这里分别实现了从服务器上拉取一个list对象、提交一个对象json数据到服务器上请求创建两个操作，分别对应Http的GET与POST请求。完整的实现代码如下：
package com.httpclient.demo; import java.io.IOException; import java.util.List; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.StringEntity; import org.apache.http.impl.client.HttpClientBuilder; import org.apache.http.util.EntityUtils; import com.google.gson.Gson; import com.google.gson.reflect.TypeToken; public class HttpClientDemo { public static void main(String[] args) { HttpClient httpClient = HttpClientBuilder.create().build(); // Use this // instead HttpGet request = new HttpGet("http://localhost:8080/clotherdye/api/myTest/list"); request.addHeader("content-type", "application/json"); request.addHeader("Accept", "application/json"); try { // get with json HttpResponse httpResponse = httpClient.execute(request); String response = EntityUtils.toString(httpResponse.getEntity()); Gson gson = new Gson(); List<PersonDto> embossList = gson.fromJson(response, new TypeToken<List<PersonDto>>(){}.getType()); if(embossList != null && embossList.size() > 0) { System.out.println("Name = " + embossList.get(0).getName()); System.out.println("Country = " + embossList.get(0).getCountry()); System.out.println("dddddddddd"); } // post data with json HttpPost httpPost = new HttpPost("http://localhost:8080/clotherdye/api/myTest/create"); httpPost.addHeader("content-type", "application/json"); httpPost.addHeader("Accept", "application/json"); PersonDto dto = new PersonDto(); dto.setName("http-client"); dto.setHobby("json parser"); dto.setCountry("US"); dto.setDegree("本科"); dto.setOccupy("tester"); String jsonString = gson.toJson(dto); StringEntity entity = new StringEntity(jsonString); httpPost.setEntity(entity); httpResponse = httpClient.execute(httpPost); response = EntityUtils.toString(httpResponse.getEntity()); System.out.println(response); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { } } }
Person对象类的代码如下：
public class PersonDto { public String getName() { return name; } public void setName(String name) { this.name = name; } public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } public String getDegree() { return degree; } public void setDegree(String degree) { this.degree = degree; } public String getOccupy() { return occupy; } public void setOccupy(String occupy) { this.occupy = occupy; } public String getHobby() { return hobby; } public void setHobby(String hobby) { this.hobby = hobby; } private String name; private String country; private String degree; private String occupy; private String hobby; }
服务器端是基于Spring3 MVC开发的Controller接口类，代码如下
import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.ResponseBody; @Controller @RequestMapping("/api/myTest") public class RestfulAPIController { @RequestMapping("/list") public @ResponseBody List<PersonDto> getList() { List<PersonDto> persons = new ArrayList<PersonDto>(); PersonDto p1 = new PersonDto(); p1.setCountry("中国"); p1.setDegree("本科"); p1.setHobby("编程"); p1.setName("zhigang"); p1.setOccupy("程序员"); PersonDto p2 = new PersonDto(); p2.setCountry("中国"); p2.setDegree("本科"); p2.setHobby("图像处理"); p2.setName("jia20003"); p2.setOccupy("码农"); persons.add(p1); persons.add(p2); System.out.println("start to get PersonDto list"); return persons; } @RequestMapping(value = "/create", method = RequestMethod.POST) @ResponseBody public Map<String, Object> createMember(@RequestBody PersonDto dto) { System.out.println(dto.getName()); System.out.println(dto.getOccupy()); Map<String, Object> map = new HashMap<String, Object>(); map.put("success", dto.getName() + "创建成功!"); return map; } }
需要特别说明的是Restful Web API应该严格遵守Http的四个操作：
GET对应查询操作
POST对应创建操作
PUT对应更新操作
DELETE对应删除操作
不应该再有其它任何操作，也就是说从HttpClient发过来的Request类型只能
是上述四种之一。否则不能称为Restful API。
JSON对象解析在HttpClient端我用了google json解析包，比较好用
推荐大家用。
