添加bean-validator.jar包

修改实体类User.java，添加默认构造器以及数据验证信息

package com.test.model;

import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;

public class User {
	private String username;
	private String nickname;
	private String password;
	private String email;

	public User() {
		super();
	}

	public User(String username, String nickname, String password, String email) {
		super();
		this.username = username;
		this.nickname = nickname;
		this.password = password;
		this.email = email;
	}

	@NotEmpty(message="邮箱不能为空！")
	@Email(message="邮箱格式不正确！")
	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public String getNickname() {
		return nickname;
	}

	public void setNickname(String nickname) {
		this.nickname = nickname;
	}

	@NotEmpty(message="密码不能为空！")
	@Size(min = 6, max = 10, message = "密码的长度必须在5到10位！")
	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	@NotEmpty(message="用户名不能为空！")
	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

}

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在Action控制器UserController.java中添加方法：

/**
 * 添加用户前
 * 
 * @param model
 * @return
 */
@RequestMapping(value = "/addUserPro", method = RequestMethod.GET)
public String addUserPro(Model model) {
	// 如果不添加下面这一句的话，sf:form标签中的modelAttribute="user"会在request中找user实例，没有的话会报错
	model.addAttribute(new User());
	return "user/addUser";
}

/**
 * 添加用户
 * 
 * @param user
 * @return
 */
@RequestMapping(value = "/addUser", method = RequestMethod.POST)
// 这里的参数user要和页面上modelAttribute属性值一致
public String addUser(@Valid User user, BindingResult br) {// 紧跟Valid参数之后写验证结果类
	if (br.hasErrors()) {
		return "user/addUser";
	}
	users.put(user.getUsername(), user);
	return InternalResourceViewResolver.REDIRECT_URL_PREFIX + "/user/userList";
}

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修改用户列表页面/jsp/user/userList.jsp添加：<a href="addUserPro">添加用户</a>

添加用户新增页面