我这里有 2 个页面，在第一页中我接受输入，然后通过使用 java 类用户验证输入数据将其显示在第二页上。
输入表格
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="/myweb/formbean.jsp" method="post">
Username : <input type="text" name="name" placeholder="name"><br>
Password : <input type="text" name="password" placeholder="password">
<input type="submit" value="OK">
</form>
</body>
</html>
显示表格
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<jsp:useBean id="id1" class="test.user" scope="session" ></jsp:useBean>
<jsp:setProperty property="*" name="id1" />
<h1> <jsp:getProperty property="name" name="id1"/> </h1>
<h1> <jsp:getProperty property="password" name="id1"/> </h1>
<h1> <jsp:getProperty property="message" name="id1"/> </h1>
<%= id1.validate() %>
</body>
</html>
JAVA用户类
public class user {
private String name;
private String password;
private String message;
public user() {
validate();
}
public user(String name, String password) {
this.name = name;
this.password = password;
validate();
}
public void setMessage(String message) {
this.message = message;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getMessage() {
return message;
}
public void validate() {
if (name == null) {
message = "name cannot be null";
} else if (password == null) {
message = "passowrd cannot be null";
}
message="form validatuion ok";
}
}
当我提交表单参数消息值时永远不会更新它总是显示消息“名称不能为空” 不确定我在这里做错了什么，请帮我弄清楚。
最佳答案
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<jsp:useBean id="id1" class="test.user" scope="session" ></jsp:useBean>
<jsp:setProperty property="*" name="id1" />
<h1> <jsp:getProperty property="name" name="id1"/> </h1>
<h1> <jsp:getProperty property="password" name="id1"/> </h1>
//==========================================
<%= id1.validate() %>
<h1> <jsp:getProperty property="message" name="id1"/> </h1>
//==========================================
</body>
</html>
//==============================================================
public void validate() {
if (name==null){message="name cannot be null";}
else if(password==null) {message="passowrd cannot be null";}
else{message="form validatuion ok";}
}
关于java - JSP bean 值未更新，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32213537/