Jersey 客户端示例 – Jersey2 客户端 API

Jersey 客户端示例 – Jersey2 客户端 API

原文： https://howtodoinjava.com/jersey/jersey-restful-client-examples/

Jersey 2 客户端 API 从专有的 Jersey 1.x 客户端 API 中得到启发。在此 Jersey 客户端示例中，我们将学习构建客户端 API 并调用不同的 REST 方法并使用 API 结果。

Table of Contents

1\. Jersey Client Maven
2\. Jersey ClientBuilder
3\. HTTP GET - Collection/List of Entities
4\. HTTP GET - Single Entity
5\. HTTP POST
6\. HTTP PUT
7\. HTTP DELETE
8\. Model classes and Configuration files

1. Jersey 客户端 Maven

在pom.xml文件中添加 jersey 客户端 maven 依赖项。

<dependency>
    <groupId>org.glassfish.jersey.core</groupId>
    <artifactId>jersey-client</artifactId>
    <version>2.25.1</version>
</dependency>

2. Jersey `ClientBuilder`

JAX-RS 客户端 API 设计为允许流畅的编程模型。要创建 Jersey 客户端，请按照以下步骤操作：

使用ClientBuilder.newClient()静态方法。
在上面获得的客户端实例上使用client.target()方法。
在第二步中获得的WebTarget实例上，使用webTarget.request()方法获取Invocation.Builder。
执行invocationBuilder.get()，put()，post()或delete()方法以调用相应的 REST API。

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFilter.class ) );

WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("employees");

Invocation.Builder invocationBuilder =  webTarget.request(MediaType.APPLICATION_XML);

Response response = invocationBuilder.post(Entity.entity(emp, MediaType.APPLICATION_XML));

下面给出的示例将有助于我们更好地理解并为开发任务做好准备。我建议您浏览其他 Jersey 示例，例如文件上传示例和文件下载示例。

3. HTTP GET – 实体的集合/列表

REST API

这是用于检索系统中所有员工的 API 代码。

@GET
@Path("/employees")
@Produces(MediaType.APPLICATION_XML)
public Employees getAllEmployees() 
{
	Employees list = new Employees();
	list.setEmployeeList(new ArrayList<Employee>());

	list.getEmployeeList().add(new Employee(1, "Lokesh Gupta"));
	list.getEmployeeList().add(new Employee(2, "Alex Kolenchiskey"));
	list.getEmployeeList().add(new Employee(3, "David Kameron"));

	return list;
}

Jersey 客户端代码

此 RESTful 客户端代码将访问上述 API，并在控制台中打印响应。

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFilter.class ) );
WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("employees");

Invocation.Builder invocationBuilder =	webTarget.request(MediaType.APPLICATION_XML);
Response response = invocationBuilder.get();

Employees employees = response.readEntity(Employees.class);
List<Employee> listOfEmployees = employees.getEmployeeList();

System.out.println(response.getStatus());
System.out.println(Arrays.toString( listOfEmployees.toArray(new Employee[listOfEmployees.size()]) ));

Output:

200
[Employee [id=1, name=Lokesh Gupta], Employee [id=2, name=Alex Kolenchiskey], Employee [id=3, name=David Kameron]]

4. HTTP GET – 单一实体

这是 API 代码，用于根据其 ID 检索单个员工。

@GET
@Path("/employees/{id}")
@Produces(MediaType.APPLICATION_XML)
public Response updateEmployeeById(@PathParam("id") Integer id) 
{
	if(id  < 0){
		return Response.noContent().build();
	}
	Employee emp = new Employee();

	emp.setId(id);
	emp.setName("Lokesh Gupta");

	GenericEntity<Employee> entity = new GenericEntity<Employee>(emp, Employee.class);
	return Response.ok().entity(entity).build();
}

客户端代码

此 RESTful 客户端代码将访问上述 API，并在控制台中打印响应。

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFilter.class ) );
WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("employees").path("1");

Invocation.Builder invocationBuilder =	webTarget.request(MediaType.APPLICATION_XML);
Response response = invocationBuilder.get();

Employee employee = response.readEntity(Employee.class);

System.out.println(response.getStatus());
System.out.println(employee);

Output:

200
Employee [id=1, name=Lokesh Gupta]

5. HTTP POST

这是用于在集合中添加员工的 API 代码。

@POST
@Path("/employees")
@Consumes(MediaType.APPLICATION_XML)
@Produces(MediaType.APPLICATION_XML)
public Response addEmployee( Employee e ) throws URISyntaxException 
{
	if(e == null){
		return Response.status(400).entity("Please add employee details !!").build();
	}

	if(e.getName() == null) {
		return Response.status(400).entity("Please provide the employee name !!").build();
	}

	return Response.created(new URI("/rest/employees/"+e.getId())).build();
}

Jersey 客户端代码

此 RESTful 客户端代码将访问上述 API，并在控制台中打印响应。

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFilter.class ) );
WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("employees");

Employee emp = new Employee();
emp.setId(1);
emp.setName("David Feezor");

Invocation.Builder invocationBuilder =	webTarget.request(MediaType.APPLICATION_XML);
Response response = invocationBuilder.post(Entity.entity(emp, MediaType.APPLICATION_XML));

System.out.println(response.getStatus());
System.out.println(response.readEntity(String.class));

Output:

201

6. HTTP PUT

这是 API 代码，用于通过其 ID 更新员工名称。

@PUT
@Path("/employees/{id}")
@Consumes(MediaType.APPLICATION_XML)
@Produces(MediaType.APPLICATION_XML)
public Response updateEmployeeById(@PathParam("id") Integer id, Employee e) 
{
	Employee updatedEmployee = new Employee();

	if(e.getName() == null) {
		return Response.status(400).entity("Please provide the employee name !!").build();
	}

	updatedEmployee.setId(id);
	updatedEmployee.setName(e.getName());

	return Response.ok().entity(updatedEmployee).build();
}

Jersey2 客户端代码

此 RESTful 客户端代码将访问上述 API，并在控制台中打印响应。

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFilter.class ) );
WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("employees").path("1");

Employee emp = new Employee();
emp.setId(1);
emp.setName("David Feezor");

Invocation.Builder invocationBuilder =	webTarget.request(MediaType.APPLICATION_XML);
Response response = invocationBuilder.put(Entity.entity(emp, MediaType.APPLICATION_XML));

Employee employee = response.readEntity(Employee.class);

System.out.println(response.getStatus());
System.out.println(employee);

Output:

200
Employee [id=1, name=David Feezor]

7. HTTP DELETE

这是用于通过 ID 从集合中删除员工的 API 代码。

@DELETE
@Path("/employees/{id}")
public Response deleteEmployeeById(@PathParam("id") Integer id) 
{		
	return Response.status(202).entity("Employee deleted successfully !!").build();
}

Jersey 客户端代码

此 RESTful 客户端代码将访问上述 API，并在控制台中打印响应。

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFilter.class ) );
WebTarget webTarget = client.target("http://localhost:8080/JerseyDemos/rest").path("employees").path("1");

Invocation.Builder invocationBuilder =	webTarget.request();
Response response = invocationBuilder.delete();

System.out.println(response.getStatus());
System.out.println(response.readEntity(String.class));

Output:

202
Employee deleted successfully !!

8. 模型类和配置文件

下面列出了其他用于创建此 Jersey2 客户端示例的文件。

`Employees.java`

package com.howtodoinjava.jersey;

import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "employeeList")
@XmlAccessorType (XmlAccessType.FIELD)
public class Employees 
{
	@XmlElement(name="employee")
	private List<Employee> employeeList;

	public List<Employee> getEmployeeList() {
		return employeeList;
	}

	public void setEmployeeList(List<Employee> employeeList) {
		this.employeeList = employeeList;
	}
}

`Employee.java`

package com.howtodoinjava.jersey;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "employee")
@XmlAccessorType (XmlAccessType.FIELD)
public class Employee 
{
	private Integer id;
	private String name;

	public Employee() {

	}

	public Employee(Integer id, String name) {
		this.id  = id;
		this.name = name;
	}

	public Integer getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

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

	@Override
	public String toString() {
		return "Employee [id=" + id + ", name=" + name + "]";
	}
}

`pom.xml`

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd;
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.howtodoinjava.jersey</groupId>
	<artifactId>JerseyDemos</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<repositories>
		<repository>
			<id>maven2-repository.java.net</id>
			<name>Java.net Repository for Maven</name>
			<url>http://download.java.net/maven/2/</url>
			<layout>default</layout>
		</repository>
	</repositories>
	<properties>
		<jersey2.version>2.19</jersey2.version>
		<jaxrs.version>2.0.1</jaxrs.version>
	</properties>
	<dependencies>
		<!-- JAX-RS -->
		<dependency>
			<groupId>javax.ws.rs</groupId>
			<artifactId>javax.ws.rs-api</artifactId>
			<version>${jaxrs.version}</version>
		</dependency>
		<!-- Jersey2.19 -->
		<dependency>
			<groupId>org.glassfish.jersey.containers</groupId>
			<artifactId>jersey-container-servlet</artifactId>
			<version>${jersey2.version}</version>
		</dependency>
		<dependency>
			<groupId>org.glassfish.jersey.core</groupId>
			<artifactId>jersey-server</artifactId>
			<version>${jersey2.version}</version>
		</dependency>
		<dependency>
			<groupId>org.glassfish.jersey.core</groupId>
			<artifactId>jersey-client</artifactId>
			<version>${jersey2.version}</version>
		</dependency>
		<dependency>
			<groupId>org.glassfish.jersey.media</groupId>
			<artifactId>jersey-media-multipart</artifactId>
			<version>${jersey2.version}</version>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.jaxrs</groupId>
			<artifactId>jackson-jaxrs-json-provider</artifactId>
			<version>2.4.1</version>
		</dependency>
	</dependencies>
	<build>
		<finalName>JerseyDemos</finalName>
		<plugins>
			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<source>1.7</source>
					<target>1.7</target>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

`web.xml`

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

	<display-name>Archetype Created Web Application</display-name>

	<servlet>
		<servlet-name>jersey-serlvet</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.howtodoinjava.jersey</param-value>
		</init-param>
		<init-param>
			<param-name>jersey.config.server.provider.classnames</param-name>
			<param-value>org.glassfish.jersey.filter.LoggingFilter</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<servlet-mapping>
		<servlet-name>jersey-serlvet</servlet-name>
		<url-pattern>/rest/*</url-pattern>
	</servlet-mapping>

</web-app>

在下面将您的问题和评论发送给我。

学习愉快！

参考：

Jersey 客户端 Java 文档