RESTful Web服务-方法

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📜 RESTful Web服务-方法

📅 最后修改于: 2020-10-20 04:38:15 🧑 作者: Mango

到目前为止，我们已经讨论了RESTful Web服务大量使用HTTP动词来确定要在指定资源上执行的操作。下表列出了HTTP动词的常见用法示例。

HTTP Method	GET
URI	http://localhost:8080/UserManagement/rest/UserService/users
Operation	Get list of users
Operation Type	Read Only

HTTP Method	GET
URI	http://localhost:8080/UserManagement/rest/UserService/users/1
Operation	Get user of Id 1
Operation Type	Read Only

HTTP Method	POST
URI	http://localhost:8080/UserManagement/rest/UserService/users/2
Operation	Insert user with Id 2
Operation Type	Non-Idempotent

HTTP Method	PUT
URI	http://localhost:8080/UserManagement/rest/UserService/users/2
Operation	Update User with Id 2
Operation Type	N/A

HTTP Method	DELETE
URI	http://localhost:8080/UserManagement/rest/UserService/users/1
Operation	Delete User with Id 1
Operation Type	Idempotent

HTTP Method	OPTIONS
URI	http://localhost:8080/UserManagement/rest/UserService/users
Operation	List the supported operations in web service
Operation Type	Read Only

HTTP Method	HEAD
URI	http://localhost:8080/UserManagement/rest/UserService/users
Operation	Returns only HTTP Header, no Body
Operation Type	Read Only

这里是要考虑的重要点：

GET操作是只读的并且是安全的。
PUT和DELETE操作是幂等的，这意味着无论调用多少次这些操作，其结果都将始终相同。
PUT和POST操作几乎相同，不同之处仅在于PUT操作是幂等的，而POST操作可能导致不同的结果。

例

让我们更新在RESTful Web服务-第一个应用程序教程中创建的示例，以创建可以执行CRUD（创建，读取，更新，删除）操作的Web服务。为简单起见，我们使用文件I / O代替数据库操作。

更新com.tutorialspoint包下的UserService.java ， User.java ， UserDao.java文件。

User.java

package com.tutorialspoint;

import java.io.Serializable;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement(name = "user")
public class User implements Serializable {

   private static final long serialVersionUID = 1L;
   private int id;
   private String name;
   private String profession;

   public User(){}

   public User(int id, String name, String profession){
      this.id = id;
      this.name = name;
      this.profession = profession;
   }

   public int getId() {
      return id;
   }
   @XmlElement
   public void setId(int id) {
      this.id = id;
   }
   public String getName() {
      return name;
   }
   @XmlElement
      public void setName(String name) {
      this.name = name;
   }
   public String getProfession() {
      return profession;
   }
   @XmlElement
   public void setProfession(String profession) {
      this.profession = profession;
   }    

   @Override
   public boolean equals(Object object){
      if(object == null){
         return false;
      }else if(!(object instanceof User)){
         return false;
      }else {
         User user = (User)object;
         if(id == user.getId()
            && name.equals(user.getName())
            && profession.equals(user.getProfession())
         ){
            return true;
         }            
      }
      return false;
   }    
}

UserDao.java

package com.tutorialspoint;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;

public class UserDao {
   public List getAllUsers(){
      List userList = null;
      try {
         File file = new File("Users.dat");
         if (!file.exists()) {
            User user = new User(1, "Mahesh", "Teacher");
            userList = new ArrayList();
            userList.add(user);
            saveUserList(userList);        
         }
         else{
            FileInputStream fis = new FileInputStream(file);
            ObjectInputStream ois = new ObjectInputStream(fis);
            userList = (List) ois.readObject();
            ois.close();
         }
      } catch (IOException e) {
         e.printStackTrace();
      } catch (ClassNotFoundException e) {
         e.printStackTrace();
      }        
      return userList;
   }

   public User getUser(int id){
      List users = getAllUsers();

      for(User user: users){
         if(user.getId() == id){
            return user;
         }
      }
      return null;
   }

   public int addUser(User pUser){
      List userList = getAllUsers();
      boolean userExists = false;
      for(User user: userList){
         if(user.getId() == pUser.getId()){
            userExists = true;
            break;
         }
      }        
      if(!userExists){
         userList.add(pUser);
         saveUserList(userList);
         return 1;
      }
      return 0;
   }

   public int updateUser(User pUser){
      List userList = getAllUsers();

      for(User user: userList){
         if(user.getId() == pUser.getId()){
            int index = userList.indexOf(user);            
            userList.set(index, pUser);
            saveUserList(userList);
            return 1;
         }
      }        
      return 0;
   }

   public int deleteUser(int id){
      List userList = getAllUsers();

      for(User user: userList){
         if(user.getId() == id){
            int index = userList.indexOf(user);            
            userList.remove(index);
            saveUserList(userList);
            return 1;   
         }
      }        
      return 0;
   }

   private void saveUserList(List userList){
      try {
         File file = new File("Users.dat");
         FileOutputStream fos;

         fos = new FileOutputStream(file);

         ObjectOutputStream oos = new ObjectOutputStream(fos);        
         oos.writeObject(userList);
         oos.close();
      } catch (FileNotFoundException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

UserService.java

package com.tutorialspoint;

import java.io.IOException;
import java.util.List;

import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.OPTIONS;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;

@Path("/UserService")
public class UserService {
    
   UserDao userDao = new UserDao();
   private static final String SUCCESS_RESULT="success";
   private static final String FAILURE_RESULT="failure";


   @GET
   @Path("/users")
   @Produces(MediaType.APPLICATION_XML)
   public List getUsers(){
      return userDao.getAllUsers();
   }

   @GET
   @Path("/users/{userid}")
   @Produces(MediaType.APPLICATION_XML)
   public User getUser(@PathParam("userid") int userid){
      return userDao.getUser(userid);
   }

   @POST
   @Path("/users")
   @Produces(MediaType.APPLICATION_XML)
   @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
   public String createUser(@FormParam("id") int id,
      @FormParam("name") String name,
      @FormParam("profession") String profession,
      @Context HttpServletResponse servletResponse) throws IOException{
      User user = new User(id, name, profession);
      int result = userDao.addUser(user);
      if(result == 1){
         return SUCCESS_RESULT;
      }
      return FAILURE_RESULT;
   }

   @PUT
   @Path("/users")
   @Produces(MediaType.APPLICATION_XML)
   @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
   public String updateUser(@FormParam("id") int id,
      @FormParam("name") String name,
      @FormParam("profession") String profession,
      @Context HttpServletResponse servletResponse) throws IOException{
      User user = new User(id, name, profession);
      int result = userDao.updateUser(user);
      if(result == 1){
         return SUCCESS_RESULT;
      }
      return FAILURE_RESULT;
   }

   @DELETE
   @Path("/users/{userid}")
   @Produces(MediaType.APPLICATION_XML)
   public String deleteUser(@PathParam("userid") int userid){
      int result = userDao.deleteUser(userid);
      if(result == 1){
         return SUCCESS_RESULT;
      }
      return FAILURE_RESULT;
   }

   @OPTIONS
   @Path("/users")
   @Produces(MediaType.APPLICATION_XML)
   public String getSupportedOperations(){
      return "GET, PUT, POST, DELETE";
   }
}

现在使用Eclipse，将您的应用程序导出为war文件，并将其部署在tomcat中。要使用Eclipse创建WAR文件，请遵循选项文件->导出-> Web>战争文件，最后选择项目UserManagement和目标文件夹。要在Tomcat中部署war文件，请将UserManagement.war放置在Tomcat安装目录> webapps目录中，然后启动Tomcat。

测试Web服务

Jersey提供了用于创建Web服务客户端以测试Web服务的API。我们在同一项目的com.tutorialspoint包下创建了一个示例测试类WebServiceTester.java 。

WebServiceTester.java

package com.tutorialspoint;

import java.util.List;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Entity;
import javax.ws.rs.core.Form;
import javax.ws.rs.core.GenericType;
import javax.ws.rs.core.MediaType;

public class WebServiceTester  {

   private Client client;
   private String REST_SERVICE_URL = "http://localhost:8080/UserManagement/rest/UserService/users";
   private static final String SUCCESS_RESULT="success";
   private static final String PASS = "pass";
   private static final String FAIL = "fail";

   private void init(){
      this.client = ClientBuilder.newClient();
   }

   public static void main(String[] args){
      WebServiceTester tester = new WebServiceTester();
      //initialize the tester
      tester.init();
      //test get all users Web Service Method
      tester.testGetAllUsers();
      //test get user Web Service Method 
      tester.testGetUser();
      //test update user Web Service Method
      tester.testUpdateUser();
      //test add user Web Service Method
      tester.testAddUser();
      //test delete user Web Service Method
      tester.testDeleteUser();
   }
   //Test: Get list of all users
   //Test: Check if list is not empty
   private void testGetAllUsers(){
      GenericType> list = new GenericType>() {};
      List users = client
         .target(REST_SERVICE_URL)
         .request(MediaType.APPLICATION_XML)
         .get(list);
      String result = PASS;
      if(users.isEmpty()){
         result = FAIL;
      }
      System.out.println("Test case name: testGetAllUsers, Result: " + result );
   }
   //Test: Get User of id 1
   //Test: Check if user is same as sample user
   private void testGetUser(){
      User sampleUser = new User();
      sampleUser.setId(1);

      User user = client
         .target(REST_SERVICE_URL)
         .path("/{userid}")
         .resolveTemplate("userid", 1)
         .request(MediaType.APPLICATION_XML)
         .get(User.class);
      String result = FAIL;
      if(sampleUser != null && sampleUser.getId() == user.getId()){
         result = PASS;
      }
      System.out.println("Test case name: testGetUser, Result: " + result );
   }
   //Test: Update User of id 1
   //Test: Check if result is success XML.
   private void testUpdateUser(){
      Form form = new Form();
      form.param("id", "1");
      form.param("name", "suresh");
      form.param("profession", "clerk");

      String callResult = client
         .target(REST_SERVICE_URL)
         .request(MediaType.APPLICATION_XML)
         .put(Entity.entity(form,
            MediaType.APPLICATION_FORM_URLENCODED_TYPE),
            String.class);
      String result = PASS;
      if(!SUCCESS_RESULT.equals(callResult)){
         result = FAIL;
      }

      System.out.println("Test case name: testUpdateUser, Result: " + result );
   }
   //Test: Add User of id 2
   //Test: Check if result is success XML.
   private void testAddUser(){
      Form form = new Form();
      form.param("id", "2");
      form.param("name", "naresh");
      form.param("profession", "clerk");

      String callResult = client
         .target(REST_SERVICE_URL)
         .request(MediaType.APPLICATION_XML)
         .post(Entity.entity(form,
            MediaType.APPLICATION_FORM_URLENCODED_TYPE),
            String.class);
   
      String result = PASS;
      if(!SUCCESS_RESULT.equals(callResult)){
         result = FAIL;
      }

      System.out.println("Test case name: testAddUser, Result: " + result );
   }
   //Test: Delete User of id 2
   //Test: Check if result is success XML.
   private void testDeleteUser(){
      String callResult = client
         .target(REST_SERVICE_URL)
         .path("/{userid}")
         .resolveTemplate("userid", 2)
         .request(MediaType.APPLICATION_XML)
         .delete(String.class);

      String result = PASS;
      if(!SUCCESS_RESULT.equals(callResult)){
         result = FAIL;
      }

      System.out.println("Test case name: testDeleteUser, Result: " + result );
   }
}

现在，使用Eclipse运行测试器。右键单击该文件，然后按照选项Run as-> Java Application运行。您将在Eclipse控制台中看到以下结果：

Test case name: testGetAllUsers, Result: pass
Test case name: testGetUser, Result: pass
Test case name: testUpdateUser, Result: pass
Test case name: testAddUser, Result: pass
Test case name: testDeleteUser, Result: pass

打印