本文详细介绍了如何使用Restlet框架构建RESTful Web服务，包括创建JavaWeb工程、引入相关Jar、设计Model、实现BusinessObject、创建Resource类以及配置web.xml文件。文章还展示了如何使用客户端进行资源操作，如查询、更新和删除。此外，通过实例说明了如何在应用中添加更多资源以实现业务逻辑的分离。
1、示例说明
版本：Restlet版本为2.1.0。
相关：实例是使用Restlet自身的Application和Component组件。
2、创建Java Web工程，添加相关Jar。实例中工程名为RestletService
3、创建Model，示例为Student
public class Student {
private Integer id;
private String name;
private Integer sex;
private Integer age;
public Student() {
}
/**setter/getter**/
}4、创建BusinessObject类，示例虚拟了一个数据库和相应的一些操作
public class StudentBO {
private static Map<Integer, Student> students = new HashMap<Integer, Student>();
// next Id
private static int nextId = 5;
static {
students.put(1, new Student(1, "Michael", 1, 18));
students.put(2, new Student(2, "Anthony", 1, 22));
students.put(3, new Student(3, "Isabella", 0, 19));
students.put(4, new Student(4, "Aiden", 1, 20));
}
public Student getStudent(Integer id) {
return students.get(id);
}
public List<Student> getStudentAll() {
return new ArrayList<Student>(students.values());
}
public Integer saveOrUpdateStudent(Student student) {
if (student.getId() == null) {
student.setId(nextId++);
}
students.put(student.getId(), student);
return student.getId();
}
public Integer removeStudent(Integer id) {
students.remove(id);
return id;
}
}5、创建对应的Resource类，具体看注释
(1)、StudentResource类，主要针对单一查询，修改和删除操作
public class StudentResource extends ServerResource {
private int id;
private StudentBO studentService = new StudentBO();
/**
* 用来获取传递过来的studentId占位符的值
*/
@Override
protected void doInit() throws ResourceException {
id = Integer.valueOf((String) getRequestAttributes().get("studentId"));
}
@Get("json")
public Student getStudent(){
return studentService.getStudent(id);
}
@Delete
public Integer deleteStudent() {
return studentService.removeStudent(id);
}
@Put("json")
public Integer updateStudent(Student student){
student.setId(id);
return studentService.saveOrUpdateStudent(student);
}
/*
* 第二种传入参数和返回值的方式
* @Put
* public Representation put(Representation entity) throws ResourceException {
* //entity这样一个对象将会把客户端传进来参数保存在其中，通过如下方式可以获取参数值
* Form form = new Form(entity);
* Student student = new Student();
* String name = form.getFirstValue("name");
* int sex = Integer.parseInt(form.getFirstValue("sex"));
* int age = Integer.parseInt(form.getFirstValue("age"));
* student.setName(name);
* student.setSex(sex);
* student.setAge(age);
* student.setId(id);
* studentService.saveOrUpdateStudent(student)；
* //实例返回的是String类型的扩展，当然你也可以返回JsonRepresentation这样一个扩展
* return new StringRepresentation(student.toString()); //为了更好的说明返回整个对象
*
* }
*/
}(2)、StudentListResource类，主要针对多返回查询和新增操作
public class StudentListResource extends ServerResource {
private StudentBO studentService = new StudentBO();
@Get("json")
public List<Student> get(Representation entity) {
List<Student> studentList = studentService.getStudentAll();
return studentList;
}
@Post("json")
public Integer saveStudent(Student student) {
return studentService.saveOrUpdateStudent(student);
}
}6、扩展org.restlet.Application类
public class StudentApplication extends Application {
/**
* 重写createInboundRoot通过attach方法绑定资源类，并且制定了访问路径
*/
@Override
public Restlet createInboundRoot() {
Router router = new Router(getContext());
router.attach("/student/{studentId}", StudentResource.class);
router.attach("/student", StudentListResource.class);
return router;
}
}7、配置web.xml
<context-param>
<param-name>org.restlet.application</param-name>
<!-- 自定义org.restlet.Application扩展类 -->
<param-value>com.rc.rl.StudentApplication</param-value>
</context-param>
<servlet>
<servlet-name>RestletServlet</servlet-name>
<servlet-class>org.restlet.ext.servlet.ServerServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>RestletServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
8、Test客户端
/**
*客户端使用了Junit4
*/
public class StudentClient {
@Test
public void student_findById() {
try {
ClientResource client = new ClientResource(
"http://localhost:8080/RestletService/student/1");
Representation representation = client.get();
System.out.println(representation.getText());
} catch (Exception e) {
e.printStackTrace();
}
}
public void student_delete() {
try {
ClientResource client = new ClientResource(
"http://localhost:8080/RestletService/student/1");
Representation representation = client.delete();
System.out.println(representation.getText());
} catch (Exception e) {
e.printStackTrace();
}
}
@Test
public void student_put() {
try {
Student student = new Student("Test_Put", 0, 23);
ClientResource client = new ClientResource(
"http://localhost:8080/RestletService/student/2");
Representation representation = client.put(student, MediaType.APPLICATION_JAVA_OBJECT);
System.out.println(representation.getText());
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* StudentResource中第二种传入参数和返回值的方式的客户端调用方式
*/
@Test
public void student_put_other() {
try {
Form queryForm = new Form();
queryForm.add("name", "steven4");
queryForm.add("sex", "2");
queryForm.add("age", "300");
ClientResource client = new ClientResource(
"http://localhost:8080/RestletService/student/2");
Representation representation = client.put(queryForm.getWebRepresentation());
System.out.println(representation.getText());
} catch (Exception e) {
e.printStackTrace();
}
}
@Test
public void student_post() {
try {
Student student = new Student("Test_Put", 0, 23);
ClientResource client = new ClientResource(
"http://localhost:8080/RestletService/student");
Representation representation = client.post(student, MediaType.APPLICATION_JAVA_OBJECT);
System.out.println(representation.getText());
} catch (Exception e) {
e.printStackTrace();
}
}
@Test
public void student_getAll() {
try {
ClientResource client = new ClientResource(
"http://localhost:8080/RestletService/student");
Representation representation = client.get();
System.out.println(representation.getText());
} catch (Exception e) {
e.printStackTrace();
}
}
}说明：以上的org.restlet.Application的使用示例。
9、org.restlet.Component的使用
在上面的实例中，如果需要加入Teacher等更多资源时，或许为了业务逻辑的分离，就不能再把TeacherResource也在StudentApplication中进行绑定。
解决办法是如同上面所示建立Teacher相关的Resource和针对Teacher的org.restlet.Application扩展，然后扩展org.restlet.Component如下：
public class RestSimpleComponent extends Component {
public RestSimpleComponent() {
getDefaultHost().attach("/stu",new StudentApplication());
getDefaultHost().attach("/tea",new TeacherApplication());
}
}再修改web.xml中<context-param/>如下：
<context-param>
<!-- <param-name>org.restlet.application</param-name>
<param-value>com.rc.rl.RestSimpleApplication</param-value> -->
<param-name>org.restlet.component</param-name>
<param-value>com.rc.rl.RestSimpleComponent</param-value>
</context-param>
注意：通过如上配置之后，访问的URI需要加上Component中添加的路径，如之前的 http://localhost:8080/RestletService/student/1将变更为 http://localhost:8080/RestletService/stu/student/1
转载于:https://blog.51cto.com/racoguo/1243045
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