import java.lang.reflect.Field;
import javax.swing.JFrame;
import javax.swing.BorderFactory;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.border.TitledBorder;
import javax.swing.JPanel;
import javax.swing.JOptionPane;
import java.awt.BorderLayout;
import java.awt.AWTEvent;
import java.awt.Component;
import java.awt.Container;
import java.awt.Color;
import javax.swing.text.JTextComponent;
import javax.swing.UIManager;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.lang.reflect.Modifier;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
public class ViewClassInfoFrame
extends JFrame
implements ActionListener{
//输入类名单行文本框
private JTextField classNameField =
new JTextField();
//查看类信息按钮
private JButton viewInfoButtom =
new JButton();
//提示输入类名的标签
private JLabel hintLabel =
new JLabel();
//显示类信息的多行文本框
private JTextArea InfoTextArea =
new JTextArea();
//滚动容器，不能独立存在
private JScrollPane infoScrollPane =
new JScrollPane();
//一个标题边框，提示结果信息
private TitledBorder titledBorder;
//容器，可以盛放其他控件，不能单独存在
private JPanel upPanel =
new JPanel();
private JPanel centerPanel =
new JPanel();
//容器的布局管理器，边界划分，分为东南西北中，默认为CENTER
private BorderLayout mainFrameBorderLayout =
new BorderLayout();
private BorderLayout centerFrameBorderLayout =
new BorderLayout();
private BorderLayout upFrameBorderLayout =
new BorderLayout();
//通过构造函数创建对象实例时，初始化窗口和窗口中的组件
public ViewClassInfoFrame(){
//java.awt.Component，激活当前的窗口事件省略了this
// enableEvents(AWTEvent.WINDOW_EVENT_MASK);
init();
//初始化窗口
//java.awt.Container，当前窗口中GUI重新布局,生效
// validate();
}
private void init(){
//初始化文本输入框
classNameField.setFont(
new java.awt.Font("Dialog", 0, 15
));
classNameField.setSelectedTextColor(java.awt.Color.WHITE);
classNameField.setText("");
//清空文本
//初始化按钮和标签
viewInfoButtom.setFont(
new java.awt.Font("Dialog", 0, 13
));
viewInfoButtom.setText("查看类信息"
);
//将按钮事件注册到监听队列
viewInfoButtom.addActionListener(
this);
hintLabel.setFont(new java.awt.Font("Dialog", 0, 17
));
hintLabel.setText("请输入完整的类名："
);
//初始化文本域，不可编辑，初始为空
InfoTextArea.setFont(
new java.awt.Font("Dialog", 0, 13
));
InfoTextArea.setEditable(false);
InfoTextArea.setText(""
);
//初始化标题框，因为BorderFactory.createEtchedBorder()是静态方法，所以没有生成实例变量对象
titledBorder =
new TitledBorder(javax.swing.BorderFactory.createEtchedBorder(Color.white,
new Color(134,134,134)), "结果信息"
);
//初始化滚动容器--包含标题边框
infoScrollPane.setBorder(titledBorder);
//向滚动容器中的视口或悬窗(观看的窗口)添加多行文本框组件
infoScrollPane.getViewport().add(InfoTextArea,
null);
//利用布局管理器将容器放入容器
upPanel.setLayout(upFrameBorderLayout);
upPanel.add(hintLabel, BorderLayout.NORTH);
upPanel.add(classNameField, BorderLayout.CENTER);
upPanel.add(viewInfoButtom, BorderLayout.SOUTH);
//将滚动容器和内部的组件放到centerPanel面板
centerPanel.setLayout(centerFrameBorderLayout);
centerPanel.add(infoScrollPane, BorderLayout.CENTER);
//获取当前窗口的内容容器,设置布局管理器
this.getContentPane().setLayout(mainFrameBorderLayout);
this.setSize(
new Dimension(650, 560
));
this.setTitle("使用反射机制查看java的类信息"
);
//向窗口内容容器中添加容器
this.getContentPane().add(upPanel, BorderLayout.NORTH);
this.getContentPane().add(centerPanel, BorderLayout.CENTER);
//设置当前顶级容器操作的默认操作
this.getRootPane().setDefaultButton(viewInfoButtom);
//进程监听窗口的关闭事件
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
//实现ActionListener接口，处理鼠标事件，方法一定要是public
public void actionPerformed(ActionEvent e){
//从文本输入框获取输入的内容
String className =
classNameField.getText();
StringBuffer buf =
new StringBuffer();
try{
//利用反射获取类型系的背景是不知道类具体信息，仅知道类名或全限名(包路径+类名)
Class c =
Class.forName(className);
buf.append(" /**类的声明**/\n"
);
buf.append(getClassStatement(c));
buf.append("\n"
);
buf.append(" /**字段**/\n"
);
buf.append(getClassFields(c));
buf.append("\n"
);
buf.append(" /**构造函数**/\n"
);
buf.append(getClassConstructors(c));
buf.append("\n"
);
buf.append(" /**方法**/\n"
);
buf.append(getClassMethods(c));
buf.append("\n"
);
}catch(Exception e1){
//调用对话框展示提示信息
JOptionPane.showMessageDialog(
this, "没找到该类："+
e1.getMessage());
}
//在多行文本框中展示类信息
InfoTextArea.setText(buf.toString());
}
//获取类的声明信息
private String getClassStatement(Class c){
StringBuffer buf =
new StringBuffer();
if(c. getName().equals("java.lang.Object"
)){
buf.append("public class Object{"
);
}else{
String superClass =
c.getSuperclass().getName();
buf.append("public class "
).append(c.getName());
buf.append(" extends ").append(superClass).append(" {"
);
}
return buf.toString();
}
//获取Field信息
private String getClassFields(Class c){
StringBuffer buf =
new StringBuffer();
Field[] fields =
c.getDeclaredFields();
for(Field f:fields){
//将Field的访问控制符转换为String类型
String modifier =
Modifier.toString(f.getModifiers());
String type =
f.getType().getName();
buf.append(modifier).append(" ").append(type).append(" ").append(f.getName()).append(";\n"
);
}
return buf.toString();
}
//获取构造函数信息
private String getClassConstructors(Class c){
Constructor[] constructors =
c.getDeclaredConstructors();
StringBuffer buf =
new StringBuffer();
for(Constructor con:constructors){
//获取构造器的访问控制符
String modifier =
Modifier.toString(con.getModifiers());
buf.append(modifier).append(" ").append(con.getName()).append(" ("
);
//获取构造函数所有参数类型
Class[] paremeters =
con.getParameterTypes();
for(
int i=0;i<paremeters.length;i++
){
if(i==(paremeters.length-1
)){
buf.append(paremeters[i].getName());
}
else{
buf.append(paremeters[i].getName()).append(", "
);
}
}
buf.append(")"
);
Class[] excepTypes =
con.getExceptionTypes();
for(
int i=0;i<excepTypes.length;i++
){
if(i==0
){
buf.append("throws "
);
}
if(i==(excepTypes.length-1
)){
buf.append(excepTypes[i].getName());
}else{buf.append(excepTypes[i].getName()).append(", "
);}
}
buf.append("\n"
);
}
return buf.toString();
}
//获取所有方法信息
private String getClassMethods(Class c){
Method[] methods =
c.getDeclaredMethods();
StringBuffer buf =
new StringBuffer();
for(Method method:methods){
String modifier =
Modifier.toString(method.getModifiers());
String type =
method.getReturnType().getName();
String name =
method.getName();
buf.append(modifier).append(" ").append(type).append(" ").append(name).append("("
);
Class[] parameters =
method.getParameterTypes();
for(
int i=0;i<parameters.length;i++
){
if(i==0
){
buf.append(parameters[i].getName()).append(", "
);
}
if(i==(parameters.length-1
)){
buf.append(parameters[i].getName());
}else{buf.append(parameters[i].getName()).append(", "
);}
}
buf.append(") "
);
Class[] excepTypes =
method.getExceptionTypes();
for(
int i=0;i<excepTypes.length;i++
){
if(i==0
){
buf.append("throws "
).append(excepTypes[i].getName());
}
if(i==(excepTypes.length-1
)){
buf.append(excepTypes[i].getName());
}else{buf.append(excepTypes[i].getName()).append(", "
);}
}
buf.append("\n"
);
}
return buf.toString();
}
public static void main(String[] args){
//设置界面的外观，为系统外观
// try{
// UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
// }catch(Exception e){
// e.printStackTrace();
// }
ViewClassInfoFrame frame =
new ViewClassInfoFrame();
//获取屏幕分辨率，使窗体居中
Dimension screenSize =
Toolkit. getDefaultToolkit().getScreenSize();
Dimension frameSize =
frame.getSize();
if(frameSize.height >
screenSize.height){
frameSize.height =
screenSize.height;
}
if(frameSize.width >
screenSize.width){
frameSize.width =
screenSize.width;
}
frame.setLocation((screenSize.width - frameSize.width)/2, (screenSize.height - frameSize.height)/2
);
frame.setVisible(true);
}
}
执行结果：
转载于:https://www.cnblogs.com/celine/p/9426833.html
相关资源：数据结构—成绩单生成器
