## 實現 我們將創建一個作為模型的*Student*對象。*StudentView*是一個把學生詳細信息輸出到控制臺的視圖類，*StudentController*是負責存儲數據到*Student*對象中的控制器類，并相應地更新視圖*StudentView*。 *MVCPatternDemo*，我們的演示類使用*StudentController*來演示 MVC 模式的用法。 ## 步驟 1 創建模型。 Student.java ``` public class Student { private String rollNo; private String name; public String getRollNo() { return rollNo; } public void setRollNo(String rollNo) { this.rollNo = rollNo; } public String getName() { return name; } public void setName(String name) { this.name = name; } } ``` ## 步驟 2 創建視圖。 ## StudentView.java ``` public class StudentView { public void printStudentDetails(String studentName, String studentRollNo){ System.out.println("Student: "); System.out.println("Name: " + studentName); System.out.println("Roll No: " + studentRollNo); } } ``` ## 步驟 3 創建控制器。 ## StudentController.java ``` public class StudentController { private Student model; private StudentView view; public StudentController(Student model, StudentView view){ this.model = model; this.view = view; } public void setStudentName(String name){ model.setName(name); } public String getStudentName(){ return model.getName(); } public void setStudentRollNo(String rollNo){ model.setRollNo(rollNo); } public String getStudentRollNo(){ return model.getRollNo(); } public void updateView(){ view.printStudentDetails(model.getName(), model.getRollNo()); } } ``` ## 步驟 4 使用*StudentController*方法來演示 MVC 設計模式的用法。 ## MVCPatternDemo.java ``` public class MVCPatternDemo { public static void main(String[] args) { Student model = retrieveStudentFromDatabase(); //從數據庫獲取學生記錄 StudentView view = new StudentView(); //創建一個視圖：把學生詳細信息輸出到控制臺 StudentController controller = new StudentController(model, view); controller.updateView(); controller.setStudentName("John"); //更新模型數據 controller.updateView(); } private static Student retrieveStudentFromDatabase(){ Student student = new Student(); student.setName("Robert"); student.setRollNo("10"); return student; } } ``` ## 步驟 5 執行程序，輸出結果： ~~~ Student: Name: Robert Roll No: 10 Student: Name: John Roll No: 10 ~~~