代码一
错误Cannot find a method to write property [username] of type [java.lang.String] in a bean of type [cn.hbsi.daomain.User]
```javascript
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" import="cn.hbsi.dao.UserDao,cn.hbsi.dao.service.UserDaoImpl" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户名检测</title>
</head>
<body>
<jsp:useBean id="user" class="cn.hbsi.daomain.User"></jsp:useBean>
<jsp:setProperty property="username" name="user" param="username"/>
<%
UserDao ud= new UserDaoImpl();
boolean flag=ud.checkUsername(user.getUsername());
//定义一个变量uservalidate 如果为ok说明用户可以注册
String uservalidate="no";
//将用户名保存到request域中
request.setAttribute("uname", user.getUsername());
if(flag){
request.setAttribute("usermessage", "用户名已被注册，请重新输入");
}else{
request.setAttribute("usermessage", "用户名有效，可注册");
uservalidate="ok";
}
request.setAttribute("userflag", uservalidate);
%>
<jsp:forward page="register.jsp"></jsp:forward>
</body>
</html>
--------------------------------------------------
代码2()
package cn.hbsi.daomain;
//实体类
public class User {
private int id;
private String username;
private String password;
private String usertypes;
private String verify;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
public String getUsertypes() {
return usertypes;
}
public void setUsertypes(String usertypes) {
this.usertypes = usertypes;
}
public String getVerify() {
return verify;
}
public void setVerify(String verify) {
this.verify = verify;
}
}
```
你看下其他字段有没有这种问题。
如果其他字段正常，改下属性名。
第13行代码property="username"改成property="*"试试，如果你表单里的属性也是username，其实param="username"是可以省略的