java采用标签实现分页

package real.tags; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.HashMap; import javax.servlet.http.HttpServletRequest; import javax.servlet.jsp.JspException; import javax.servlet.jsp.tagext.BodyTagSupport; import javax.sql.rowset.CachedRowSet; import com.sun.rowset.CachedRowSetImpl; public class Pagination extends BodyTagSupport { private CachedRowSet _crs; private CachedRowSet _rs; private String _sql; private String _method; private int _curpage; private int _totalpage; private int _count; private String _url; private String _driver; // private String _searthText="where 'a='a'"; // 表名 private String tableName; private String databaseName; private String var; private String curPageCountName="curPageCount"; private String totalPageCountName="totalPageCount"; private String username; private String password; private String dataBaseAddressName="localhost"; private String dataBaseAddressPort="1433"; private String sql="select * from "+tableName; // 要显示的页数 private String count="5"; private void load() { HttpServletRequest req=(HttpServletRequest)this.pageContext.getRequest(); this._method=req.getParameter("method"); // this._searthText=req.getParameter("searthText"); this._crs=(CachedRowSet)this.pageContext.getSession().getAttribute("crs"); if(this._crs==null) { init(); } // if(this._searthText!=null){ // this._sql="select * from "+tableName+_searthText; // try { // this._crs.setCommand(this._sql); // this._crs.execute(); // } catch (SQLException e) { // e.printStackTrace(); // } // } if(_method==null) { _method="first"; } System.out.println("-------------------------"+this.pageContext.getSession().getAttribute(curPageCountName).toString()); this._curpage=Integer.valueOf(this.pageContext.getSession().getAttribute(curPageCountName).toString()); this._totalpage=Integer.valueOf(this.pageContext.getSession().getAttribute(totalPageCountName).toString()); try{ this._crs.afterLast(); if(_method.equals("first")){ while(this._crs.previousPage()){} this._crs.beforeFirst(); _curpage=1; } else if(_method.equals("priv")) { if(this._crs.previousPage()) _curpage--; else{ this._crs.beforeFirst(); } } else if(_method.equals("next")){ if(this._crs.nextPage())_curpage++; else{ this._crs.previousPage(); } } else{ while(this._crs.nextPage()){} _curpage=_totalpage; this._crs.afterLast(); this._crs.previousPage(); } if(this._crs.next()){ ResultSetMetaData me=_crs.getMetaData(); HashMap hm = new HashMap(); for(int i=1;i<_crs.getMetaData().getColumnCount()+1;i++){ hm.put(me.getColumnName(i),_crs.getObject(i)); } // this.pageContext.getRequest().setAttribute(var, _crs.getObject(1)); this.pageContext.getRequest().setAttribute(var, hm); // System.out.println(); } }catch(SQLException ex){ ex.printStackTrace(); }catch(Exception e){ e.printStackTrace(); } } public int doAfterBody() throws JspException { try { while(_crs.next()){ ResultSetMetaData me=_crs.getMetaData(); HashMap hm = new HashMap(); for(int i=1;i<=_crs.getMetaData().getColumnCount();i++){ hm.put(me.getColumnName(i),_crs.getObject(i)); } this.pageContext.getRequest().setAttribute(var, hm); return EVAL_BODY_AGAIN; } } catch (SQLException e) { e.printStackTrace(); } return EVAL_PAGE; } @Override public int doStartTag() throws JspException { load(); return EVAL_BODY_INCLUDE; } @Override public void doInitBody() throws JspException { }; public void update(){ this.pageContext.getSession().setAttribute("crs", _crs); //this.pageContext.getSession().setAttribute("searthText" ,_searthText); this.pageContext.getSession().setAttribute(curPageCountName, _curpage); this.pageContext.getSession().setAttribute(totalPageCountName, _totalpage); } public void init(){ try { this._curpage=1; this._method="first"; this._sql=sql; this._count=Integer.valueOf(count); this._crs=new CachedRowSetImpl(); this._driver="com.microsoft.sqlserver.jdbc.SQLServerDriver"; this._url="jdbc:sqlserver://"+this.dataBaseAddressName+":"+this.dataBaseAddressPort+";databasename="+databaseName; this._crs.setUsername(username!=null?username:"sa"); this._crs.setPassword(password!=null?password:"sa"); this._crs.setUrl(_url); this._crs.setCommand(_sql); this._rs=this._crs.createCopy(); this._crs.setPageSize(Integer.valueOf(count)); Class.forName(this._driver); this._crs.execute(); while(this._crs.nextPage()){this._totalpage++;} while(this._crs.previousPage()){} update(); }catch(ClassNotFoundException ex){ System.out.println("请导入SUN公司连接数据库的JAR包"); }catch (SQLException e) { e.printStackTrace(); }catch (Exception e) { e.printStackTrace(); } } // @Override public int doEndTag() throws JspException { update(); return EVAL_PAGE; } public String getCurPageCountName() { return curPageCountName; } public void setCurPageCountName(String curPageCountName) { this.curPageCountName = curPageCountName; } public String getTableName() { return tableName; } public void setTableName(String tableName) { this.tableName = tableName; } public String getVar() { return var; } public void setVar(String var) { this.var = var; } public String getCount() { return count; } public void setCount(String count) { this.count = count; } public String getTotalPageCountName() { return totalPageCountName; } public void setTotalPageCountName(String totalPageCountName) { this.totalPageCountName = totalPageCountName; } public String getDatabaseName() { return databaseName; } public void setDatabaseName(String databaseName) { this.databaseName = databaseName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getDataBaseAddressName() { return dataBaseAddressName; } public void setDataBaseAddressName(String dataBaseAddressName) { this.dataBaseAddressName = dataBaseAddressName; } public String getDataBaseAddressPort() { return dataBaseAddressPort; } public void setDataBaseAddressPort(String dataBaseAddressPort) { this.dataBaseAddressPort = dataBaseAddressPort; } public String getSql() { return sql; } public void setSql(String sql) { this.sql = sql; } }