spring mvc（六）实现REST接口GET/POST/PUT/DELETE

基于springmvc实现restful样式的api接口。

1.Restful
Restful样式的接口将功能抽象为资源resource路径映射，以HTTP GET /resource/{id} 的方式访问。主要分为以下几类接口：

地址	请求方法	说明
/resources	GET	获取所有资源
/resources	POST	创建新资源，content中包含资源内容
/resource/{id}	GET	获取编号为id的资源
/resource/{id}	PUT	更新编号为id的资源，content中包含资源内容
/resource/{id}	DELETE	删除编号为id的资源

{id}称为路径变量，告诉restful你要对哪个资源进行查、改、删。
接口一般返回json/xml格式数据，方便服务端程序、浏览器脚本调用接口并处理返回数据。
按照Restful样式，teacher模块设计为两个资源地址：/restMvc/teachers和/restMvc/teachers/{id}。
基础的spring配置、springmvc配置、各层对象接口实现见前几节内容。

2./teachers
新建TeachersMvcResource资源类：

package com.sunbin.test.restMvc;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.view.json.MappingJackson2JsonView;
import org.springframework.stereotype.Controller;
import org.springframework.beans.factory.annotation.Autowired;

import com.sunbin.test.teacher.pojo.Teacher;
import com.sunbin.test.teacher.service.TeacherService;

@Controller
@RequestMapping("/restMvc/teachers")
public class TeachersMvcResource {

	@Autowired
	private TeacherService teacherService;

	@RequestMapping(method = { RequestMethod.GET })
	public ModelAndView get(HttpServletRequest arg0, HttpServletResponse arg1)
			throws Exception {
		System.out.println("RestMvc TeachersResource.get");
		ModelAndView modelAndView = new ModelAndView(
				new MappingJackson2JsonView());
		modelAndView.addObject("teachers", teacherService.list());
		return modelAndView;
	}

	@RequestMapping(method = { RequestMethod.POST })
	public ModelAndView post(Teacher teacher, HttpServletRequest arg0,
			HttpServletResponse arg1) throws Exception {
		ModelAndView modelAndView = new ModelAndView(
				new MappingJackson2JsonView());
		System.out.println("RestMvc TeachersResource.post:" + teacher);
		teacherService.save(teacher);
		modelAndView.addObject("status", "y");
		return modelAndView;
	}

}

类中@Controller和@RequestMapping("/restMvc/teachers")注解声明了此类是Controller类并绑定到/restMvc/teachers地址，两个方法的@RequestMapping(method = { RequestMethod.GET })和@RequestMapping(method = { RequestMethod.POST })注解分别响应GET和POST请求，Contentbody里面的参数会被自动封装成Teacher teacher。

3./teacher/{id}
新增TeacherMvcResource类：

package com.sunbin.test.restMvc;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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.servlet.ModelAndView;
import org.springframework.web.servlet.view.json.MappingJackson2JsonView;
import org.springframework.stereotype.Controller;
import org.springframework.beans.factory.annotation.Autowired;

import com.sunbin.test.teacher.pojo.Teacher;
import com.sunbin.test.teacher.service.TeacherService;

@Controller
@RequestMapping("/restMvc/teacher/{id}")
public class TeacherMvcResource {

	@Autowired
	private TeacherService teacherService;

	@RequestMapping(method = { RequestMethod.GET })
	public ModelAndView get(@PathVariable("id") Integer id,
			HttpServletRequest arg0, HttpServletResponse arg1) throws Exception {
		System.out.println("RestMvc TeacherResource.get:" + id);
		ModelAndView modelAndView = new ModelAndView(
				new MappingJackson2JsonView());
		Teacher teacher = new Teacher();
		teacher.setId(id);
		modelAndView.addObject("teacher", teacherService.get(teacher));
		return modelAndView;
	}

	@RequestMapping(method = { RequestMethod.PUT })
	public ModelAndView put(@PathVariable("id") Integer id, Teacher teacher,
			HttpServletRequest arg0, HttpServletResponse arg1) throws Exception {
		ModelAndView modelAndView = new ModelAndView(
				new MappingJackson2JsonView());
		// 如果teacher中不含id属性，需要单独设置
		// teacher.setId(id);
		System.out.println("RestMvc TeacherResource.put:" + id + ":" + teacher);
		teacherService.update(teacher);
		modelAndView.addObject("status", "y");
		return modelAndView;
	}

	@RequestMapping(method = { RequestMethod.DELETE })
	public ModelAndView delete(@PathVariable("id") Integer id,
			HttpServletRequest arg0, HttpServletResponse arg1) throws Exception {
		ModelAndView modelAndView = new ModelAndView(
				new MappingJackson2JsonView());
		Teacher teacher = new Teacher();
		teacher.setId(id);
		System.out.println("RestMvc TeacherResource.delete:" + id);
		teacherService.remove(teacher);
		modelAndView.addObject("status", "y");
		return modelAndView;
	}

}

类中将服务绑定到/restMvc/teacher/{id}地址，方法的@RequestMapping(method = { RequestMethod.GET })、@RequestMapping(method = { RequestMethod.PUT })和@RequestMapping(method = { RequestMethod.DELETE })注解分别响应GET、PUT和POST请求，@PathVariable("id") Integer id接收{id}路径变量。

4.测试
rest接口可以使用服务端程序（URL、HttpClient库）、js（jquery ajax）进行访问。这里简单实用浏览器插件来测试。
使用FireFox的HttpRquester插件访问接口：
POST
POST http://localhost:8080/testRest/restMvc/teachers
Content-Type: application/x-www-form-urlencoded
name=a&age=1
-- response --
200 OK
Server:  Apache-Coyote/1.1
Pragma:  no-cache
Cache-Control:  no-cache, no-store, max-age=0
Expires:  Thu, 01 Jan 1970 00:00:00 GMT
Content-Type:  application/json;charset=UTF-8
Content-Language:  zh-CN
Transfer-Encoding:  chunked
Date:  Tue, 23 May 2017 02:31:56 GMT

{"teacher":{"id":1,"age":1,"name":"a"},"status":"y"}

GET
GET http://localhost:8080/testRest/restMvc/teachers

-- response --
200 OK
Server:  Apache-Coyote/1.1
Pragma:  no-cache
Cache-Control:  no-cache, no-store, max-age=0
Expires:  Thu, 01 Jan 1970 00:00:00 GMT
Content-Type:  application/json;charset=UTF-8
Content-Language:  zh-CN
Transfer-Encoding:  chunked
Date:  Tue, 23 May 2017 02:36:16 GMT

{"teachers":[{"id":1,"age":1,"name":"a"}]}

PUT
PUT http://localhost:8080/testRest/restMvc/teacher/1
Content-Type: application/x-www-form-urlencoded
name=b&age=2
-- response --
200 OK
Server:  Apache-Coyote/1.1
Pragma:  no-cache
Cache-Control:  no-cache, no-store, max-age=0
Expires:  Thu, 01 Jan 1970 00:00:00 GMT
Content-Type:  application/json;charset=UTF-8
Content-Language:  zh-CN
Transfer-Encoding:  chunked
Date:  Tue, 23 May 2017 02:37:41 GMT

{"teacher":{"id":1,"age":2,"name":"b"},"status":"y"}

GET
GET http://localhost:8080/testRest/restMvc/teacher/1

-- response --
200 OK
Server:  Apache-Coyote/1.1
Pragma:  no-cache
Cache-Control:  no-cache, no-store, max-age=0
Expires:  Thu, 01 Jan 1970 00:00:00 GMT
Content-Type:  application/json;charset=UTF-8
Content-Language:  zh-CN
Transfer-Encoding:  chunked
Date:  Tue, 23 May 2017 02:38:29 GMT

{"teacher":{"id":1,"age":2,"name":"b"}}

DELETE
DELETE http://localhost:8080/testRest/restMvc/teacher/1

-- response --
200 OK
Server:  Apache-Coyote/1.1
Pragma:  no-cache
Cache-Control:  no-cache, no-store, max-age=0
Expires:  Thu, 01 Jan 1970 00:00:00 GMT
Content-Type:  application/json;charset=UTF-8
Content-Language:  zh-CN
Transfer-Encoding:  chunked
Date:  Tue, 23 May 2017 02:38:46 GMT

{"status":"y"}

5.使用服务器程序访问rest
使用HttpClient库对rest接口进行测试，测试类TestRestMvc代码如下：

package com.sunbin.test.restMvc;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class TestRestMvc {

	public static final String URL_BASE = "http://localhost:8080/testRest/restMvc/";

	public static void main(String[] args) throws ParseException,
			ClientProtocolException, IOException {
		String module = "teacher";
		String url = "";
		DefaultHttpClient client = new DefaultHttpClient();
		HttpEntity entity = null;
		String result = "";
		Map map = null;
		HttpGet httpGet = null;
		HttpPost httpPost = null;
		HttpPut httpPut = null;
		HttpDelete httpDelete = null;

		url = URL_BASE + module + "s";
		System.out.println("get\t " + url);
		httpGet = new HttpGet(url);
		result = EntityUtils.toString(client.execute(httpGet).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "s";
		System.out.println("post\t " + url);
		httpPost = new HttpPost(url);
		map = new HashMap();
		map.put("name", "a");
		map.put("age", "1");
		entity = new UrlEncodedFormEntity(getParam(map), "UTF-8");
		httpPost.setEntity(entity);
		result = EntityUtils.toString(client.execute(httpPost).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "s";
		System.out.println("get\t " + url);
		httpGet = new HttpGet(url);
		result = EntityUtils.toString(client.execute(httpGet).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "/1";
		System.out.println("get\t " + url);
		httpGet = new HttpGet(url);
		result = EntityUtils.toString(client.execute(httpGet).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "/1";
		System.out.println("put\t " + url);
		httpPut = new HttpPut(url);
		map = new HashMap();
		map.put("name", "aa");
		map.put("age", "11");
		entity = new UrlEncodedFormEntity(getParam(map), "UTF-8");
		httpPut.setEntity(entity);
		result = EntityUtils.toString(client.execute(httpPut).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "s";
		System.out.println("get\t " + url);
		httpGet = new HttpGet(url);
		result = EntityUtils.toString(client.execute(httpGet).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "/1";
		System.out.println("delete\t " + url);
		httpDelete = new HttpDelete(url);
		result = EntityUtils.toString(client.execute(httpDelete).getEntity());
		System.out.println(result);

		url = URL_BASE + module + "s";
		System.out.println("get\t " + url);
		httpGet = new HttpGet(url);
		result = EntityUtils.toString(client.execute(httpGet).getEntity());
		System.out.println(result);

	}

	public static List<NameValuePair> getParam(Map parameterMap) {
		List<NameValuePair> param = new ArrayList<NameValuePair>();
		Iterator it = parameterMap.entrySet().iterator();
		while (it.hasNext()) {
			Entry parmEntry = (Entry) it.next();
			param.add(new BasicNameValuePair((String) parmEntry.getKey(),
					(String) parmEntry.getValue()));
		}
		return param;
	}
}

输出结果如下：
get http://localhost:8080/testRest/restMvc/teachers
{"teachers":[]}
post http://localhost:8080/testRest/restMvc/teachers
{"teacher":{"id":1,"age":1,"name":"a"},"status":"y"}
get http://localhost:8080/testRest/restMvc/teachers
{"teachers":[{"id":1,"age":1,"name":"a"}]}
get http://localhost:8080/testRest/restMvc/teacher/1
{"teacher":{"id":1,"age":1,"name":"a"}}
put http://localhost:8080/testRest/restMvc/teacher/1
{"teacher":{"id":1,"age":11,"name":"aa"},"status":"y"}
get http://localhost:8080/testRest/restMvc/teachers
{"teachers":[{"id":1,"age":11,"name":"aa"}]}
delete http://localhost:8080/testRest/restMvc/teacher/1
{"status":"y"}
get http://localhost:8080/testRest/restMvc/teachers
{"teachers":[]}