如何在jsp:setProperty中设置request.getParameter [英] How to set request.getParameter in jsp:setProperty
问题描述
我使用bean/表单处理在登录屏幕上获取输入参数,然后使用这些参数尝试将用户登录到应用程序中.
I used beans/form processing to take input parameters on login screen and then with those parameters try and log the user into the application.
但是我遇到错误-
org.apache.jasper.JasperException:/loginbean.jsp(6,59)属性值request.getParameter("userName")引用为,在val中使用时必须转义
org.apache.jasper.JasperException: /loginbean.jsp(6,59) Attribute value request.getParameter("userName") is quoted with " which must be escaped when used within the val
出现此错误的代码行是下面给出的代码块中的第二行- (即名称为"userName"的属性的代码行)
The line of code which has this error is the second line in the block of code given below- (ie line of code for the property with name='userName')
loginbean.jsp
<jsp:useBean id="db" scope="request" class="logbean.LoginBean" >
<jsp:setProperty name="db" property="userName" value="<%=request.getParameter("userName")%>"/>
<jsp:setProperty name="db" property="password" value="<%=request.getParameter("password")%>"/>
</jsp:useBean>
LoginBean.java
package logbean;
public class LoginBean {
String userName="";
String password="";
public String getUserName() {
return userName;
}
public void setUsername(String username) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
推荐答案
在这里,
<jsp:setProperty name="db" property="userName" value="<%=request.getParameter("userName")%>"/>
<jsp:setProperty name="db" property="password" value="<%=request.getParameter("password")%>"/>
您正在尝试混合使用 scriptlets 和taglib.这是无效的.使用一个或另一个.当userName
将包含一个双引号,例如foo"bar
时,那么JSP标记的值基本上将以value="foo"bar"
结束.这在语法上是无效的.
you're attempting to mix scriptlets and taglibs. This is invalid. Use the one or the other. When the userName
would contain a doublequote like foo"bar
then the value of the JSP tag will basically end up like value="foo"bar"
. This is syntactically invalid.
由于 scriptlets 是 dead 技术,我建议您完全摆脱它.正确的方法是使用 EL .在EL中,所有请求参数都可以通过隐式变量${param}
作为Map<String, String>
使用.利用它.
Since scriptlets is a dead technology, I'd suggest to just get rid of it altogether. The proper way would be to use EL. In EL, all request parameters are available as a Map<String, String>
through the implicit variable ${param}
. Make use of it.
<jsp:setProperty name="db" property="userName" value="${param.userName}"/>
<jsp:setProperty name="db" property="password" value="${param.password}"/>
或者,当所有参数名称与属性名称相同时,也可以让JSP自动设置所有属性,如下所示:
Alternatively, you can also let JSP automagically set all properties as below when all parameter names are the same as property names anyway:
<jsp:setProperty name="db" property="*"/>
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