Restlet - 使用Restlet自身組件Application/Component的開發實例

一、示例說明

   版本：Restlet版本爲2.1.0。

   相關：實例是使用Restlet自身的Application和Component組件。

二、建立Java Web工程，添加相關Jar。實例中工程名爲RestletService

三、建立Model，示例爲Student

publicclassStudent {
privateInteger id;
privateString name;
privateInteger sex;
privateInteger age;
publicStudent() {
}
/**setter/getter**/
}

四、建立BusinessObject類，示例虛擬了一個數據庫和相應的一些操做

publicclassStudentBO {
privatestaticMap<Integer, Student> students = newHashMap<Integer, Student>();
// next Id
privatestaticintnextId = 5;
static{
students.put(1, newStudent(1, "Michael", 1, 18));
students.put(2, newStudent(2, "Anthony", 1, 22));
students.put(3, newStudent(3, "Isabella", 0, 19));
students.put(4, newStudent(4, "Aiden", 1, 20));
}
publicStudent getStudent(Integer id) {
returnstudents.get(id);
}
publicList<Student> getStudentAll() {
returnnewArrayList<Student>(students.values());
}
publicInteger saveOrUpdateStudent(Student student) {
if(student.getId() == null) {
student.setId(nextId++);
}
students.put(student.getId(), student);
returnstudent.getId();
}
publicInteger removeStudent(Integer id) {
students.remove(id);
returnid;
}
}

五、建立對應的Resource類，具體看註釋

   (1)、StudentResource類，主要針對單一查詢，修改和刪除操做

publicclassStudentResource extendsServerResource {
privateintid;
privateStudentBO studentService = newStudentBO();
/**
* 用來獲取傳遞過來的studentId佔位符的值
*/
@Override
protectedvoiddoInit() throwsResourceException {
id = Integer.valueOf((String) getRequestAttributes().get("studentId"));
}
@Get("json")
publicStudent getStudent(){
returnstudentService.getStudent(id);
}
@Delete
publicInteger deleteStudent() {
returnstudentService.removeStudent(id);
}
@Put("json")
publicInteger updateStudent(Student student){ 
student.setId(id);
returnstudentService.saveOrUpdateStudent(student);
}
/*
* 第二種傳入參數和返回值的方式
* @Put
* public Representation put(Representation entity) throws ResourceException {
*    //entity這樣一個對象將會把客戶端傳進來參數保存在其中，經過以下方式能夠獲取參數值
*    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)；
*    //實例返回的是String類型的擴展，固然你也能夠返回JsonRepresentation這樣一個擴展
*    return new StringRepresentation(student.toString()); //爲了更好的說明返回整個對象
*
* }
*/
}

   (2)、StudentListResource類，主要針對多返回查詢和新增操做

publicclassStudentListResource extendsServerResource {
privateStudentBO studentService = newStudentBO();
@Get("json")
publicList<Student> get(Representation entity) {
List<Student> studentList = studentService.getStudentAll();
returnstudentList;
}
@Post("json")
publicInteger saveStudent(Student student) {
returnstudentService.saveOrUpdateStudent(student);
}
}

六、擴展org.restlet.Application類

publicclassStudentApplication extendsApplication {
/**
* 重寫createInboundRoot經過attach方法綁定資源類，而且制定了訪問路徑
*/
@Override
publicRestlet createInboundRoot() {
Router router = newRouter(getContext());
router.attach("/student/{studentId}", StudentResource.class);
router.attach("/student", StudentListResource.class);
returnrouter;
}
}

七、配置web.xml

<context-param>
<param-name>org.restlet.application</param-name>
<!-- 自定義org.restlet.Application擴展類  -->
<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>

八、Test客戶端

/**
*客戶端使用了Junit4
*/
publicclassStudentClient {
@Test
publicvoidstudent_findById() {
try{
ClientResource client = newClientResource(
"http://localhost:8080/RestletService/student/1");
Representation representation = client.get();
System.out.println(representation.getText());
} catch(Exception e) {
e.printStackTrace();
}
}
publicvoidstudent_delete() {
try{
ClientResource client = newClientResource(
"http://localhost:8080/RestletService/student/1");
Representation representation = client.delete();
System.out.println(representation.getText());
} catch(Exception e) {
e.printStackTrace();
}
}
@Test
publicvoidstudent_put() {
try{
Student student = newStudent("Test_Put", 0, 23);
ClientResource client = newClientResource(
"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中第二種傳入參數和返回值的方式的客戶端調用方式
*/
@Test
publicvoidstudent_put_other() {
try{
Form queryForm = newForm();
queryForm.add("name", "steven4");
queryForm.add("sex", "2");
queryForm.add("age", "300");
ClientResource client = newClientResource(
"http://localhost:8080/RestletService/student/2");
Representation representation = client.put(queryForm.getWebRepresentation());
System.out.println(representation.getText());
} catch(Exception e) {
e.printStackTrace();
}
}
@Test
publicvoidstudent_post() {
try{
Student student = newStudent("Test_Put", 0, 23);
ClientResource client = newClientResource(
"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
publicvoidstudent_getAll() {
try{
ClientResource client = newClientResource(
"http://localhost:8080/RestletService/student");
Representation representation = client.get();
System.out.println(representation.getText());
} catch(Exception e) {
e.printStackTrace();
}
}
}

說明：以上的org.restlet.Application的使用示例。

九、org.restlet.Component的使用

   在上面的實例中，若是須要加入Teacher等更多資源時，或許爲了業務邏輯的分離，就不能再把TeacherResource也在StudentApplication中進行綁定。

   解決辦法是如同上面所示創建Teacher相關的Resource和針對Teacher的org.restlet.Application擴展，而後擴展org.restlet.Component以下：

publiccla***estSimpleComponent extendsComponent {
publicRestSimpleComponent() {
getDefaultHost().attach("/stu",newStudentApplication());
getDefaultHost().attach("/tea",newTeacherApplication());
}
}

   再修改web.xml中<context-param/>以下：

<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：經過如上配置以後，訪問的URI須要加上Component中添加的路徑，如以前的 http://localhost:8080/RestletService/student/1將變動爲 http://localhost:8080/RestletService/stu/student/1