resteasy_Eclipse和Tomcat的RESTEasy教程

resteasy

Welcome to RESTEasy Tutorial. RESTEasy is the JAX-RS implementation provided by JBoss project. We can use RESTEasy to create restful web services. RESTEasy provides tighter integration with the JBoss Application Server but we can deploy it on any servlet container. So today we will learn how to create restful web service using RestEasy framework and deploy in Tomcat servlet container to test it.

欢迎使用RESTEasy教程。 RESTEasy是JBoss项目提供的JAX-RS实现。 我们可以使用RESTEasy创建宁静的Web服务。 RESTEasy提供了与JBoss Application Server的更紧密的集成，但是我们可以将其部署在任何servlet容器上。 因此，今天我们将学习如何使用RestEasy框架创建Restful Web服务并部署在Tomcat Servlet容器中进行测试。

RESTEasy教程 (RESTEasy Tutorial)

Some of the features of RESTEasy framework are:

RESTEasy框架的一些功能包括：

• JAX-RS API compliant – so mostly you need to plug it with JAX-RS API coding to create rest web services.
  兼容JAX-RS API-因此大多数情况下，您需要使用JAX-RS API编码将其插入以创建其余的Web服务。
• Runs on almost any servlet container supporting Java 6 or higher
  在几乎所有支持Java 6或更高版本的servlet容器上运行
• Provides support for writing client programs using JAX-RS 2.0 client API. We will look into test program too.
  提供对使用JAX-RS 2.0客户端API编写客户端程序的支持。 我们也会研究测试程序。
• Rich set of providers – XML, JSON, YAML, Multipart, XOP, Atom, etc.
  丰富的提供程序集-XML，JSON，YAML，Multipart，XOP，Atom等
• OAuth2 and Distributed SSO with JBoss AS7
  OAuth2和带有JBoss AS7的分布式SSO
• EJB, Seam, Guice, Spring, and Spring MVC integration
  EJB，Seam，Guice，Spring和Spring MVC集成

RESTEasy示例 (RESTEasy Example)

Below are the URIs we will be exposing in our RestEasy web service implementation.

以下是我们将在RestEasy Web服务实现中公开的URI。

URI	HTTP Method	Description
/employee/add	POST	Add an employee
/employee/getDummy	GET	returns a dummy employee object
/employee/{id}/get	GET	Get the employee with ‘id’ in the URI
/employee/getAll	GET	Get all employees
/employee/{id}/delete	DELETE	Delete employee with ‘id’ in the URI

URI	HTTP方法	描述
/员工/添加	开机自检	新增员工
/员工/ getDummy	得到	返回一个虚拟员工对象
/ employee / {id} / get	得到	获取URI中带有“ id”的员工
/员工/ getAll	得到	获取所有员工
/ employee / {id} / delete	删除	删除URI中带有“ id”的员工

RESTEasy示例Eclipse项目 (RESTEasy Example Eclipse Project)

Below image shows our final project structure. First of all create a “Dynamic Web Application” in Eclipse and then convert it to Maven project to get the web project skeleton.

下图显示了我们的最终项目结构。 首先，在Eclipse中创建“动态Web应用程序”，然后将其转换为Maven项目以获取Web项目框架。

Let’s look into different components of our RestEasy web services project.

让我们研究一下RestEasy Web服务项目的不同组件。

RESTEasy示例模型类 (RESTEasy Example Model Classes)

We have two model classes – Employee for employee object and GenericResponse for sending client response object for status, message and error code.

我们有两个模型类– Employee用于雇员对象， GenericResponse用于发送客户端响应对象的状态，消息和错误代码。

package com.journaldev.jaxrs.model;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "employee")
public class Employee {
	private String name;
	private double salary;
	private int id;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	@Override
	public String toString() {
		return id + "::" + name + "::" + salary;
	}

}

package com.journaldev.jaxrs.model;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "response")
public class GenericResponse {

	private boolean status;
	private String message;
	private String errorCode;

	public boolean isStatus() {
		return status;
	}

	public void setStatus(boolean status) {
		this.status = status;
	}

	public String getMessage() {
		return message;
	}

	public void setMessage(String message) {
		this.message = message;
	}

	public String getErrorCode() {
		return errorCode;
	}

	public void setErrorCode(String errorCode) {
		this.errorCode = errorCode;
	}

	@Override
	public String toString() {
		return status + "|" + message + "|" + errorCode;
	}
}

Notice that both the java beans are annotated with @XmlRootElement annotation. This is required for JAXB API for converting objects to xml and vice versa.

请注意，两个Java Bean都使用@XmlRootElement注释进行了注释。 这是JAXB API所必需的，用于将对象转换为xml，反之亦然。

RESTEasy示例服务类 (RESTEasy Example Service Classes)

Let’s first create an interface for all the operations we are trying to expose in our restful web service.

首先，我们为尝试在静态Web服务中公开的所有操作创建一个接口。

package com.journaldev.jaxrs.service;

import javax.ws.rs.core.Response;

import com.journaldev.jaxrs.model.Employee;

public interface EmployeeService {

	public Response addEmployee(Employee e);
	
	public Response deleteEmployee(int id);
	
	public Employee getEmployee(int id);
	
	public Employee[] getAllEmployees();

}

Below is the implementation class for above employee service interface.

以下是上述员工服务接口的实现类。

package com.journaldev.jaxrs.service;


import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import com.journaldev.jaxrs.model.Employee;
import com.journaldev.jaxrs.model.GenericResponse;

@Path("/employee")
@Consumes(MediaType.APPLICATION_XML)
@Produces(MediaType.APPLICATION_XML)
public class EmployeeServiceImpl implements EmployeeService {

	private static Map emps = new HashMap();
	
	@Override
	@POST
    @Path("/add")
	public Response addEmployee(Employee e) {
		GenericResponse response = new GenericResponse();
		if(emps.get(e.getId()) != null){
			response.setStatus(false);
			response.setMessage("Employee Already Exists");
			response.setErrorCode("EC-01");
			return Response.status(422).entity(response).build();
		}
		emps.put(e.getId(), e);
		response.setStatus(true);
		response.setMessage("Employee created successfully");
		return Response.ok(response).build();
	}

	@Override
	@DELETE
    @Path("/{id}/delete")
	public Response deleteEmployee(@PathParam("id") int id) {
		GenericResponse response = new GenericResponse();
		if(emps.get(id) == null){
			response.setStatus(false);
			response.setMessage("Employee Doesn't Exists");
			response.setErrorCode("EC-02");
			return Response.status(404).entity(response).build();
		}
		emps.remove(id);
		response.setStatus(true);
		response.setMessage("Employee deleted successfully");
		return Response.ok(response).build();
	}

	@Override
	@GET
	@Path("/{id}/get")
	public Employee getEmployee(@PathParam("id") int id) {
		return emps.get(id);
	}
	
	@GET
	@Path("/{id}/getDummy")
	public Employee getDummyEmployee(@PathParam("id") int id) {
		Employee e = new Employee();
		e.setSalary(8976.55);
		e.setName("Dummy");
		e.setId(id);
		return e;
	}

	@Override
	@GET
	@Path("/getAll")
	public Employee[] getAllEmployees() {
		Set ids = emps.keySet();
		Employee[] e = new Employee[ids.size()];
		int i=0;
		for(Integer id : ids){
			e[i] = emps.get(id);
			i++;
		}
		return e;
	}

}

We are using only JAX-RS API annotations such as @Path, @PathParam, Response etc. Notice that I am using javax.ws.rs.core.Response as response object in some of the methods where I want to send the HTTP status code other than 200.

我们只使用JAX-RS API注释，比如@Path ， @PathParam ， Response等。请注意，我用javax.ws.rs.core.Response作为响应对象中的一些，我想发送的HTTP状态的方法200以外的代码。

RESTEasy配置 (RESTEasy Configuration)

We haven’t done anything related to RestEasy till now, it’s time now to configure RestEasy as our JAX-RS API implementation for our restful web service.

到目前为止，我们还没有做过与RestEasy相关的任何事情，现在是时候将RestEasy配置为我们的宁静Web服务的JAX-RS API实现。

First step is to extend javax.ws.rs.core.Application class and override few of the methods to inject our service class implementation.

第一步是扩展javax.ws.rs.core.Application类，并覆盖一些方法来注入我们的服务类实现。

package com.journaldev.jaxrs.resteasy.app;

import java.util.HashSet;
import java.util.Set;

import javax.ws.rs.core.Application;

import com.journaldev.jaxrs.service.EmployeeServiceImpl;

public class EmployeeApplication extends Application {
	
	private Set