java分页运行后无法点击换页,其他正常,求大神指教

public class PageBean {
private static final int size=5;
private int count;//总条数
private int pageSize;//每页条数
private int pageCount;//总页数
private int curPage;//当前页

public PageBean(){
    this.pageSize=size;
    curPage=1;
}
public PageBean(int pageSize){
    this.pageSize=pageSize;
    curPage=1;
}

// public int getPCount(){
// System.out.println("==============="+pageCount);
// return pageCount;
// }
public int getCount() {
//System.out.println("============"+count);
return count;
}
public void setCount(int count) {
this.count = count;
//计算总页数
this.pageCount=count%this.pageSize==0?count/this.pageSize:count/this.pageSize+1;
System.out.println("====~~~~"+pageCount);

}
public int getPageSize() {
    return pageSize;
}
public void setPageSize(int pageSize) {
    this.pageSize = pageSize;
}
public int getPageCount() {
    //this.pageCount=this.count%this.pageSize==0?this.count/this.pageSize:this.count/this.pageSize+1;

    System.out.println("==============="+pageCount);
    return this.pageCount;


}
public void setPageCount(int pageCount) {
    this.pageCount = pageCount;
}
public int getCurPage() {
    return curPage;
}
public void setCurPage(int curPage) {
    this.curPage = curPage;

}
public int prePage(){
    if(this.curPage==1){
        return 1;
    }
    return this.curPage-1;
}
public int nextPage(){
    if(this.curPage==pageCount){
        return pageCount;           
    }
    return curPage+1;
}
public int getStart(){
    return this.pageSize*(this.curPage-1);
}


public class DbDao {

private Statement st;

public DbDao(Statement st) {
    // TODO 自动生成的构造函数存根
    this.st = st;
}

public int insert(String sql) {
    int t = 0;
    try {
        t = st.executeUpdate(sql);
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }

    return t;
}

public int update(String sql) {
    int t = 0;
    try {
        t = st.executeUpdate(sql);
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }

    return t;
}

public int del(String sql) {
    int t = 0;
    try {
        t = st.executeUpdate(sql);
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }

    return t;
}

public ResultSet query(String sql) {
    ResultSet rs=null;
    try {
        rs = st.executeQuery(sql);
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }

    return rs;
}
public ResultSet pageQuery(String sql,PageBean page) {
    ResultSet rs=null;      
    try {
        int count=queryCount(sql);
        if(count==0){
            return null;
        }
        page.setCount(count);

        sql=sql+" limit "+page.getStart()+","+page.getPageSize();
        rs = st.executeQuery(sql);
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }

    return rs;
}
public int queryCount(String sql){
    String countsql="select count(*) c from ("+sql+")t";
    ResultSet rs=this.query(countsql);
    try {
        if(rs.next()){
            return rs.getInt(1);
        }
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
        return 0;
    }
    return 0;
}
@Override
protected void finalize() throws Throwable {
    // TODO 自动生成的方法存根
    super.finalize();
    if(st!=null)
    {
        st.close();
    }
}


public  <E> List<E> queryObjectList(String sql,String ClassName) throws SQLException, IllegalArgumentException, IllegalAccessException, InstantiationException, ClassNotFoundException
{
    //连接数据库

    ResultSet  rs=this.query(sql);
    ResultSetMetaData meta=rs.getMetaData();
    int count=meta.getColumnCount();//字段的数量
    Class cla=Class.forName(ClassName);
    Field[]  fs=cla.getDeclaredFields();

    List<E> list=new ArrayList<E>();

    while(rs.next())
    {
        Object obj=cla.newInstance();
        for(int i=1;i<=count;i++)//数组的字段
        {
            for(Field f:fs)//类里的属性
            {
                //类的字段名称==数据库字段名称 赋值
                if(f.getName().equals(meta.getColumnName(i))) //属性是否和字段一样
                {
                    if("INT".equals(meta.getColumnTypeName(i)))
                    {
                        f.set(obj, rs.getInt(meta.getColumnName(i)));
                    }
                    if("VARCHAR".equals(meta.getColumnTypeName(i)))
                    {
                        f.set(obj, rs.getString(meta.getColumnName(i)));
                    }

                }
            }
        }
        list.add((E)obj);
    }
    rs.close();
    return list;
}


public class Testservlet extends HttpServlet {

/**
 * 
 */
private static final long serialVersionUID = -5562520410425589914L;


@Override
protected void service(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException {
    // TODO 自动生成的方法存根
    try {
        Class.forName("com.mysql.jdbc.Driver");
    } catch (ClassNotFoundException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }//驱动
    String url = "jdbc:mysql://127.0.0.1:3306/mysql_test";//url

    Connection conn=null;
    Statement st=null;
    try {
        conn = DriverManager.getConnection(url, "root", "heihei77");
        st=conn.createStatement();
    } catch (SQLException e) {
        // TODO 自动生成的 catch 块
        e.printStackTrace();
    }
    String name="";
    Integer age=0;
    if(req.getParameter("username")!=null&&req.getParameter("username").trim()!=""){
        name=req.getParameter("username").trim();
    }
    if(req.getParameter("age")!=null&&req.getParameter("age").trim()!=""){
        age=Integer.parseInt(req.getParameter("age").trim());
    }

    //查询当前表格的数据
    DbDao dbDao = new DbDao(st);

        //ResultSet  rs=null;
        PageBean pageBean=new PageBean();
        String page=req.getParameter("page");//??????????????????????
        if(page!=null&&!"".equals(page)){
            pageBean.setCurPage(Integer.parseInt(page.trim()));
        }
        List<User> list=new ArrayList<User>();
    try {
        ResultSet rs=dbDao.pageQuery("select id,name,age from sqlpp",pageBean);

        if(rs!=null){
        while(rs.next()){
            User u=new User();
            u.setAge(rs.getInt("age"));
            u.setId(rs.getInt("id"));
            u.setName(rs.getString("name"));
            list.add(u);
        }}
        rs.close();
    } catch (SQLException e1) {
        // TODO 自动生成的 catch 块
        e1.printStackTrace();
    }
    //保存list req
    req.setAttribute("list", list);
    req.setAttribute("pageBean", pageBean);

    req.getRequestDispatcher("userList.jsp").forward(req, response);
}

1个回答

不能点击?

这不是应该是前台的嘛?

debug调试一下看下page和pagesize的值对不对,
确认一下,前台传入的时候是不是page,
String page=req.getParameter("page");

更多参考:
https://www.cnblogs.com/lantu1989/p/6403108.html

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