建立表单参数和Bean属性之间的关联
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- Example of using jsp:setProperty and an explicity associationwith an input parameter. See SaleEntry1.jspand SaleEntry3.jsp for alternatives. --><HTML><HEAD><TITLE>Using jsp:setProperty</TITLE></HEAD><BODY><TABLE BORDER=5 ALIGN="CENTER"> <TR><TH /><jsp:setProperty name="entry" property="itemID" value="<%=request.getParameter("itemID")%>" /> <jsp:setProperty name="entry" property="numItems" param="numItems" /> <jsp:setProperty name="entry" property="discountCode" param="discountCode" /><BR><TABLE ALIGN="CENTER" BORDER=1><TR property="itemID" /> <TD>$<jsp:getProperty name="entry" property="itemCost" /> <TD><jsp:getProperty name="entry" property="numItems" /> <TD>$<jsp:getProperty name="entry" property="totalCost" /></TABLE> </BODY></HTML>package bean;/** Simple bean to illustrate the various forms * of jsp:setProperty. */public class SaleEntry { private String itemID = "unknown"; private double discountCode = 1.0; private int numItems = 0; public String getItemID() { return(itemID); } public void setItemID(String itemID) { if (itemID != null) { this.itemID = itemID; } else { this.itemID = "unknown"; } } public double getDiscountCode() { return(discountCode); } public void setDiscountCode(double discountCode) { this.discountCode = discountCode; } public int getNumItems() { return(numItems); } public void setNumItems(int numItems) { this.numItems = numItems; } // Replace this with real database lookup. public double getItemCost() { double cost; if (itemID.equals("a1234")) { cost = 12.99*getDiscountCode(); } else { cost = -9999; } return(roundToPennies(cost)); } private double roundToPennies(double cost) { return(Math.floor(cost*100)/100.0); } public double getTotalCost() { return(getItemCost() * getNumItems()); }}