1.首先建立一个html页收集输入,傻子都会,传递参数为color
2.然后Servlet 收集参数,并以参数通过JavaBean建立一个实例 Bean object =new Bean(color);
3.接着通过JavaBean的get方法返回color, Servlet 进行判断.//equals() method. object.getColor();
4.servlet 判断后转到相应的jsp页面
String addr=...
核心方法: reqest.setAttribute("Instance", object);
RequestDispatcher dispatcher=request.getRequestDispatcher(addr); dispatcher .forward(request, response);
5.jsp 页面根据前面建立的实例读取相应的String. <jsp:useBean id="Instance" type="where is bean and name" scope="request"/> <jsp:getProperty name="Instance" property="String of getXXX() ‘s XXX ,here is String"/>
这个程序开始是按书上抄的,后来完全是自己写的
这下面的代码还不是很理解,到底建立了几个对象?那个是实例?特别是setAttribute("Red", color); 里是用前面的替换后边的吗?
String tempColor=request.getParameter("color"); ColorBean color=new ColorBean(tempColor);
request.setAttribute("Red", color); dispatcher.forward(request, response);
现在可以实现mvc架构了,但是,其中对象的产生过程还是不理解,对象啊,对象......
下边是源代码:
其中 Input.jsp 为收集颜色(string)页面 WantColor.java 为servlet ColorBean.java 为JavaBean 其它的是三个jsp 页面用来连接javaBean 显示颜色
越来觉得老外的书经典了,为什么我不是美国人呢? *********** //input.jsp <%@ page contentType="text/html;charset=GB2312"%> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB2312"> <title>请输入你想要的颜色</title> </head> <body> <form action="./servlet/WantColors" type=post> <input type=text name=color> <input type=submit value=submit> </form> </body> </html> ************** //wantColors.java package moonsoft.test.j2ee.wantColors; import javax.servlet.*; import javax.servlet.http.*; import java.io.PrintWriter; import java.io.IOException; public class WantColors extends HttpServlet { private static final String CONTENT_TYPE = "text/html; charset=Big5"; public void init(ServletConfig config) throws ServletException { super.init(config); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String tempColor=request.getParameter("color"); ColorBean color=new ColorBean(tempColor); if((color.getColor()==null)&&(color.getColor()).equals("")) { addr="../input.jsp"; response.sendRedirect(""); } else if(color.getColor().equals("red")) { request.setAttribute("Red", color); addr="../red.jsp"; } else if(color.getColor().equals("green")) { request.setAttribute("Green",color ); addr="../green.jsp"; } else { request.setAttribute("Blue",color ); addr="../blue.jsp"; } RequestDispatcher dispatcher=request.getRequestDispatcher(addr); dispatcher.forward(request, response); /*response.setContentType(CONTENT_TYPE); PrintWriter out = response.getWriter(); out.println("<html>"); out.println("<head><title>WantColors</title></head>"); out.println("<body>"); out.println("<p>The servlet has received a GET. This is the reply.</p>"); out.println("</body></html>"); out.close();*/ } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); /*response.setContentType(CONTENT_TYPE); PrintWriter out = response.getWriter(); out.println("<html>"); out.println("<head><title>WantColors</title></head>"); out.println("<body>"); out.println("<p>The servlet has received a POST. This is the reply.</p>"); out.println("</body></html>"); out.close();*/ } private String addr; } *********************** //ColorBean.java package moonsoft.test.j2ee.wantColors; public class ColorBean { public ColorBean(String color) { this.color=color; } public String getString() { String s="The color is :/t"; return s+color; } public String getColor() { return color; } public void setColor(String color) { this.color=color; } private String color; } ************** red.jsp <%@ page contentType="text/html;charset=Big5"%> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=Big5"> <title>red</title> </head> <body bgcolor="#FF0000"> <font color="#ffffff" size=6> <jsp:useBean id="Red" type="moonsoft.test.j2ee.wantColors.ColorBean" scope="request"/> <jsp:getProperty name="Red" property="String"/> </font> </body> </html> 那两个绿色和蓝色的copy 一下,然后改一下值就好了 |
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