一. 使用注解校验
a) 引入校验依赖包
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>2.0.0.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>5.4.1.Final</version>
</dependency>
hibernate-validator是validation-api的实现
b) 编写form元素实体类
package cultivate_web.vo;
import java.io.Serializable;
import javax.validation.constraints.Min;
import org.hibernate.validator.constraints.NotBlank;
import lombok.Data;
/**
* login页面的表单信息
* @date 2018年8月15日 下午4:41:32
*/
@Data
public class LoginForm implements Serializable {
private static final long serialVersionUID = 6057365255574064840L;
@NotBlank(message="账户不能为空!")
@Min(1000)
private String adminId;
@NotBlank(message="密码不能为空")
private String pwd;
}
校验注解是有先后顺序的,例如我的代码中@NotBlank(message="账户不能为空!")在@Min(1000)的上面,如果输入框数据为空,则会提示"不能为空",如果两个上下位置颠倒,输入框为空会提示"数值不能小于1000".
c) 编写Controller类
package cultivate_web.controller;
import javax.validation.Valid;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import cultivate_domain.pojo.Consumer;
import cultivate_web.vo.LoginForm;
@Controller
@RequestMapping(method=RequestMethod.POST)
public class PostController {
@RequestMapping("/login")
public String login( Model model,@Valid LoginForm lf,BindingResult bindingResult){
if(bindingResult.hasErrors()){
FieldError idmsg = bindingResult.getFieldError("adminId");
FieldError pwdmsg = bindingResult.getFieldError("pwd");
if(idmsg != null) model.addAttribute("idmsg", idmsg.getDefaultMessage());
if(pwdmsg != null) model.addAttribute("pwdmsg", pwdmsg.getDefaultMessage());
return "login";
}
return "";
}
}
这里要注意的是,"BindingResult bindingResult"参数必须紧跟"LoginForm lf".而且"@Valid"必须在 "LoginForm lf"的前面,我就是因为这个注解不在参数对象前面,调试几个小时没找到为什么.
d) 编写jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@page isELIgnored="false" %>
<!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=UTF-8">
<title>登录系统</title>
</head>
<body>
<h1 align="center">请使用管理员账户登录</h1>
<hr style="height: 5px">
<div style="margin-top: 100px" align="center">
<form action="login" method="post">
<table align="center" style="border-style: double; 300px; height: 200px;">
<tr>
<td>账号:</td>
<td><input id="adminId" name="adminId" type="text"/>
</td>
</tr>
<tr><td colspan="2" align="center"><span>${idmsg}</span></td></tr>
<tr>
<td>密码:</td>
<td><input id="pwd" name="pwd" type="password" /></td>
</tr>
<tr><td colspan="2" align="center"><span>${pwdmsg}</span></td></tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="提交"/></td>
</tr>
</table>
</form>
</div>
</body>
</html>
这就能做一个简单的数据校验了