pageexampleimpl.java

经典的java初学者的材料里面有最基本的java的应用

package addressbook.util;

import java.sql.ResultSet;
import java.sql.SQLException;

public class PageExampleImpl implements PageExample {
	
    protected java.sql.ResultSet rs=null;
    protected int rowsCount;
    protected int pageSize;
    protected int curPage;
    protected String command = "";
    
    public PageExampleImpl(java.sql.ResultSet rs) throws java.sql.SQLException {
        if(rs==null) throw new SQLException("given ResultSet is NULL","user");
        
        rs.last();
        rowsCount=rs.getRow();
        rs.beforeFirst();
        
        this.rs=rs;
    } 
    
    
    public int getCurPage() {
        return curPage;
    }
    
    public int getPageCount() {
        if(rowsCount==0) return 0;
        if(pageSize==0) return 1;
        //calculate PageCount
        double tmpD=(double)rowsCount/pageSize;
        int tmpI=(int)tmpD;
        if(tmpD>tmpI) tmpI++;
        return tmpI;
    }
    
    public int getPageRowsCount() {
    	//System.out.println(pageSize);
        if(pageSize==0) return rowsCount;
        //System.out.println(this.getRowsCount());
        if(getRowsCount()==0) return 0;
        if(curPage!=getPageCount()) return pageSize;
        return rowsCount-(getPageCount()-1)*pageSize;
    }
    
    public int getPageSize() {
        return pageSize;
    }
    
    public int getRowsCount() {
        return rowsCount;
    }
    
    public void gotoPage(int page) {
        if (rs == null)
            return;
        if (page < 1)
            page = 1;
        if (page > getPageCount())
            page = getPageCount();
        int row = (page - 1) * pageSize + 1;
        try {
            rs.absolute(row);
            curPage = page;
        }
        catch (java.sql.SQLException e) {
        }
    }
    
    public void pageFirst() throws java.sql.SQLException {
        int row=(curPage-1)*pageSize+1;
        rs.absolute(row);
    }
    
    public void pageLast() throws java.sql.SQLException {
        int row=(curPage-1)*pageSize+getPageRowsCount();
        rs.absolute(row);
    }
    
    public void setPageSize(int pageSize) {
        if(pageSize>=0){
            this.pageSize=pageSize;
            curPage=1;
        }
    }  
    
    public boolean next() throws SQLException {
        return rs.next();
    }
    /**
    public String getString(String columnName) throws SQLException {
        try {
            return rs.getString(columnName);
        }
        catch (SQLException e) {//这里是为了增加一些出错信息的内容便于调试
            throw new SQLException (e.toString()+" columnName="
                +columnName+" SQL="+this.getCommand());
        }
    }
    */


	public ResultSet getRs() {
		// TODO 自动生成方法存根
		return this.rs;
	}


	public void setRs(ResultSet rs) {
		// TODO 自动生成方法存根
		this.rs = rs;
	}
}