Java集合框架-2

package wk.com;

import java.awt.FlowLayout;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class test2 extends JFrame implements ActionListener {
    JFrame jframe;
    JTextField jtextfield1;
    JTextField jtextfield2;
    JTextArea jtextarea;
    List<Student> list = new ArrayList<Student>();

    public static void main(String[] args) {
        // TODO Auto-generated method stub
       test2 myJframe = new test2();// 显示窗口
    }

    test2() {
        jframe = new JFrame("成绩排序");
        jframe.setBounds(200, 100, 700, 400);
        jframe.setLayout(new FlowLayout());
        jtextfield1 = new JTextField(10);
        jtextfield2 = new JTextField(10);
        JButton jbutton = new JButton("插入");
        Box box = Box.createHorizontalBox();
        box.add(new Label("姓名:"));
        box.add(jtextfield1);
        box.add(new Label("分数:"));
        box.add(jtextfield2);
        box.add(Box.createHorizontalStrut(50));
        box.add(jbutton);
        jframe.add(box);
        jtextarea = new JTextArea(40, 80);
        jframe.add(jtextarea);
        jframe.setVisible(true);
        jbutton.addActionListener(this);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        jtextarea.setText("");
        String name = jtextfield1.getText();
        String grade = jtextfield2.getText();
        if (!"".equals(name) && !"".equals(grade)) {
            list.add(new Student(name, Float.parseFloat(grade)));
            jtextarea.append( "当前信息；姓名:" + name + "    成绩:" + grade + "\n");
        }
        Collections.sort(list);// 对list排序
        Iterator<Student> iterator = list.iterator();
        Student student;
        while (iterator.hasNext()) {
            student = iterator.next();
            jtextarea.append("姓名:" + student.name + "    成绩:" + student.grade + "\n");
        }
    }
}

class Student implements Comparable<Student> {

    String name;
    float grade;

    public Student(String name, float grade) {
        super();
        this.name = name;
        this.grade = grade;
    }

    @Override
    public int compareTo(Student o) {
        // TODO Auto-generated method stub
        return (int) (o.grade - this.grade);
    }

}