public class MyPagePanel extends JPanel{
    private final int PAGE_BTN_NUM = 6;//按钮的数目的最大值, 一定为偶数
    private JButton[] pageBtns = new JButton[PAGE_BTN_NUM];
    private JButton preBtn = new JButton("<<");//前一页
    private JButton nextBtn = new JButton(">>");//后一页
    
    private JButton jumpBtn = new JButton("跳转");
    private JTextField jumpText = new JTextField(5);//输入页号
    private JLabel totPageLabel = new JLabel("共0页");//提示一共多少页
    
    public static final int PAGE_SIZE = 2;
    private CommunicationPanel parentPanel;
    private ChatPanel chatPanel;
    //刷新某页
    public void refreshPage(){
        if(curPage == -1){
            JOptionPane.showMessageDialog(null, "请选择题目，然后再刷新!", "温馨提示",JOptionPane.WARNING_MESSAGE);
        } else {
            requestPage(curPage);
        }
    }
    //请求某页
    public void requestPage(int pageNumber){
        //当前页按钮设为 true
        if(curBtnPos >= 0)
            pageBtns[curBtnPos].setEnabled(true);
        
        JSONObject jsono = new JSONObject();
        jsono.put("problemName", JavaRequest.problemName);
        jsono.put("pageSize", String.valueOf(PAGE_SIZE));
        jsono.put("pageNumber", String.valueOf(pageNumber));
        String data = JavaRequest.sendPost("getCurProblemComments", jsono);
        
        //获取当前题目的 评论记录
        JSONObject result = JSONObject.fromObject(data);
        if((Boolean) result.get("success")){//分页显示
            JSONObject message = JSONObject.fromObject(result.get("message"));
            Map<String, Class<?>> classMap = new HashMap<String, Class<?>>();
            classMap.put("content", MyMessage.class);
            MyPage myPage = (MyPage) JSONObject.toBean(message, MyPage.class, classMap);
            this.updatePage(myPage);
        } else {
            JOptionPane.showMessageDialog(null, result.getString("message"), "温馨提示",JOptionPane.WARNING_MESSAGE);
            if(result.get("returnLogin") != null && (Boolean)result.get("returnLogin")){//如果用户登录超时返回用户登陆界面
                parentPanel.switchPanel(CommunicationPanel.LOGIN_PANEL);
            }
        }
    }
    //跳转都页面
    private void jumpPage(int pageNumber) throws Exception{
        if(pageNumber < 0 || pageNumber >= totalPages)
            throw new Exception("不存在该页号!");
        requestPage(pageNumber);
    }
    
    public MyPagePanel(CommunicationPanel parentPanelx, ChatPanel chatPanelx){
        this.parentPanel = parentPanelx;
        this.chatPanel = chatPanelx;
        
        preBtn.setEnabled(false);
        this.add(preBtn);
        preBtn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                requestPage(curPage-1);
            }
        });
        
        for(int i=0; i<pageBtns.length; ++i) {
            pageBtns[i] = new JButton();
            this.add(pageBtns[i]);
            pageBtns[i].setVisible(false);
            pageBtns[i].addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    //JButton text 表示的是页号
                    String text = ((JButton)e.getSource()).getText();
                    int pageNumber = Integer.valueOf(text);
                    requestPage(pageNumber);
                }
            });
        }
        
        nextBtn.setEnabled(false);
        this.add(nextBtn);
        nextBtn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                requestPage(curPage+1);
            }
        });
        
        jumpBtn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try{
                    if(jumpText.getText().isEmpty()) throw new Exception("页数不能为空!");
                    int pageNumber = Integer.valueOf(jumpText.getText());
                    jumpPage(pageNumber);
                } catch (Exception ex){
                    ex.printStackTrace();
                    JOptionPane.showMessageDialog(null, "请确定页号是否正确!", "温馨提示",JOptionPane.WARNING_MESSAGE);
                }
            }
        });
        this.add(totPageLabel);
        this.add(jumpText);
        this.add(jumpBtn);
    }
    private int curPage = -1, totalPages, curBtnPos = -1;
    public void updatePage(MyPage myPage){
        //清除当页面的信息
        chatPanel.getJpChat().setText("");
        //处理接受到的 评论消息
        for(MyMessage message : myPage.getContent()){
            chatPanel.addRecMsg(message.getCcontent(), StyleConstants.ALIGN_LEFT);
        }
        
        curPage = myPage.getNumber();
        totalPages = myPage.getTotalPages();
        totPageLabel.setText("共" + totalPages + "页");
        
        if(curPage == 0) preBtn.setEnabled(false);
        else preBtn.setEnabled(true);
        
        if(curPage == totalPages-1 || totalPages == 0) nextBtn.setEnabled(false);
        else nextBtn.setEnabled(true);
        
        List<Integer> pageNum = new LinkedList<Integer>();
        if(totalPages > 0) {
            int step = PAGE_BTN_NUM/2-1;
            for(int i=step; i>=1; --i) {
                if(curPage-i>=0)
                    pageNum.add(curPage-i);
            }
            
            pageNum.add(curPage);
            
            for(int i=1; i<=step+1 && curPage+i<totalPages; ++i)
                pageNum.add(curPage+i);
            
            if(pageNum.size() < PAGE_BTN_NUM){
                while(pageNum.size() < PAGE_BTN_NUM && pageNum.get(0)-1 >= 0)
                    pageNum.add(0, pageNum.get(0)-1);
                
                while(pageNum.size() < PAGE_BTN_NUM && pageNum.get(pageNum.size()-1)+1 < totalPages)
                    pageNum.add(pageNum.get(pageNum.size()-1)+1);
            }
        }
        
        int bi = 0;
        for(int pi=0; pi < pageNum.size(); ++pi, ++bi){
            pageBtns[bi].setText(String.valueOf(pageNum.get(pi)));
            if(pageNum.get(pi) == curPage){
                curBtnPos = bi;//记录这个按钮的页号值 和 当前页号值相等
            }
        }
        //重新显示按钮
        for(int i=0; i<bi; ++i)
            pageBtns[i].setVisible(true);
            
        //后面这些按钮都是没有 用上的
        for(int i=bi; i < pageBtns.length; ++i){
            pageBtns[i].setVisible(false);
        }
        
        if(totalPages > 0)
            pageBtns[curBtnPos].setEnabled(false);
    }
}

public class MyMessage{
    private String ccontent;
    private String commentid;
    public String getCcontent() {
        return ccontent;
    }
    public void setCcontent(String ccontent) {
        this.ccontent = ccontent;
    }
    public String getCommentid() {
        return commentid;
    }
    public void setCommentid(String commentid) {
        this.commentid = commentid;
    }
}

public class MyPage{
    private List<MyMessage> content;
    private boolean first;
    private boolean last;
    private int number;
    private int numberOfElements;
    private int size;
    private String totalElements;
    private String sort;
    
    public String getSort() {
        return sort;
    }

    public void setSort(String sort) {
        this.sort = sort;
    }

    public List<MyMessage> getContent() {
        return content;
    }

    public void setContent(List<MyMessage> content) {
        this.content = content;
    }

    public boolean isFirst() {
        return first;
    }

    public void setFirst(boolean first) {
        this.first = first;
    }

    public boolean isLast() {
        return last;
    }

    public void setLast(boolean last) {
        this.last = last;
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }

    public int getNumberOfElements() {
        return numberOfElements;
    }

    public void setNumberOfElements(int numberOfElements) {
        this.numberOfElements = numberOfElements;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public String getTotalElements() {
        return totalElements;
    }

    public void setTotalElements(String totalElements) {
        this.totalElements = totalElements;
    }

    public int getTotalPages() {
        return totalPages;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }



    private int totalPages;
}