Rest之路 - 第一个Rest程序

在 Eclipse 里新建一个 Dynamic project

将 Jersey 的 jar 包，拷贝到 WebContent -> WEB-INF -> lib 文件夹

Add jars to "build path"

根据业务层次编写程序

User

package com.example.tuo.rest.entity;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="user")
public class User {

	private int id;
	private String name;
	private String 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;
	}
	public User() {
		super();
		// TODO Auto-generated constructor stub
	}
	public User(int id, String name, String profession) {
		super();
		this.id = id;
		this.name = name;
		this.profession = profession;
	}

}

P.S 由于后面使用XML格式进行数据展现，在这里使用了@XMLRootElement和@XMLElement 注解。

UserDao

package com.example.tuo.rest.dao;

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;

import com.example.tuo.rest.entity.User;

public class UserDao {

	private final String CONFIG_FILE = "D:/User.dat";

	public List<User> getAllUsers()
	{
		List<User> uList = null;

		File file = new File(CONFIG_FILE);
		if(!file.exists()){
			User u = new User(1,"tuo","software engineer");
			uList= new ArrayList<User>();
			uList.add(u);
			saveUserList(uList);
		}
		else{
			FileInputStream in = null;
			ObjectInputStream oin = null;
			try {
				in = new FileInputStream(file);
				oin = new ObjectInputStream(in);
				uList=(List<User>) oin.readObject();
			} catch (FileNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (ClassNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			finally{
				try {
					if(oin != null)
						oin.close();
					if(in != null)
						in.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}

			}
		}

		return uList;
	}

	private void saveUserList(List<User> userList){
	      try {
	         File file = new File(CONFIG_FILE);
	         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();
	      }
	   }
}

在这里，使用了一个在磁盘上的文件作模拟数据库的存储

UserService

package com.example.tuo.rest.service;

import java.util.List;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import com.example.tuo.rest.dao.UserDao;
import com.example.tuo.rest.entity.User;

@Path("/UserService")
public class UserService {

	private UserDao userDao = new UserDao();

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

使用 @Path 注解，制定了 Rest 的路径（完整路径为：project/class/method）

使用 @GET 注解，标识 Rest 方法的类型

使用 @Produces(MediaType.APPLICATION_XML) 注解，标识数据表现的格式为 XML

修改 Web.xml configuration File

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>FirstHeadRestfulWebService</display-name>

  <servlet>
  	<servlet-name>My Jersey restful service</servlet-name>
  	<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
         <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>com.example.tuo.rest.service</param-value>
         </init-param>
  </servlet>
  <servlet-mapping>
  	<servlet-name>My Jersey restful service</servlet-name>
  	<url-pattern>/rest/*</url-pattern>
  </servlet-mapping>

</web-app>

注： 橙色部分表明需要扫描的包， 即 service 所在的 package

启动Rest服务并且验证

输入rest 服务地址 http://localhost:8080/FirstHeadRestfulWebService/rest/UserService/users

FirstHeadRestfulWebService - 项目目录(名称)

rest - web.xml配置的根目录

UserService/users - Class 路径 + Method 路径