从.Net到Java学习第十一篇——SpringBoot登录实现

从.Net到Java学习系列目录

通过前面10篇文章的学习，相信我们对SpringBoot已经有了一些了解，那么如何来验证我们的学习成果呢？当然是通过做项目来证明啦！所以从这一篇开始我将会对之前自己做的.net项目用java来重写。这一篇，我们来现实登录模块。

一提到登录，我们首先想到的基本的功能点就有如下：

输入：用户名、密码、验证码。

登录成功后，跳转到后台。如果未登录直接访问后台，将会跳转到登录页面。

这里暂不考虑复杂的登录实现。

技术选型，沿用前面用到的知识点。那么这里较之于之前的文章，新用到的一个就是图片验证码，一个就是权限拦截器了。

1、新建spring boot web项目，具体配置信息如pom.xml所示：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.yujie</groupId>
    <artifactId>website</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>website</name>
    <description>通用角色权限管理系统</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.13.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--集成druid，使用连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.0</version>
        </dependency>
        <!--thymeleaf-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>net.sourceforge.nekohtml</groupId>
            <artifactId>nekohtml</artifactId>
            <version>1.9.22</version>
        </dependency>
        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.1.2</version>
        </dependency>
        <!--单元测试-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!-- mybatis generator 自动生成代码插件 -->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

</project>

2、准备数据库、数据表。这里只用一张用户表t_user.sql

/*
Navicat MySQL Data Transfer

Source Server         : localhost
Source Server Version : 50717
Source Host           : localhost:3306
Source Database       : rightcontrol

Target Server Type    : MYSQL
Target Server Version : 50717
File Encoding         : 65001

Date: 2018-07-13 11:19:03
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `t_user`
-- ----------------------------
DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user` (
  `Id` int(4) NOT NULL AUTO_INCREMENT,
  `UserName` varchar(20) DEFAULT NULL COMMENT '用户名（登录）',
  `RealName` varchar(20) DEFAULT NULL COMMENT '姓名',
  `PassWord` char(32) DEFAULT NULL COMMENT '密码',
  `RoleId` int(4) DEFAULT NULL COMMENT '角色ID',
  `Status` bit(1) DEFAULT NULL COMMENT '状态',
  `CreateOn` datetime DEFAULT NULL COMMENT '创建时间',
  `UpdateOn` datetime DEFAULT NULL COMMENT '修改时间',
  `CreateBy` int(4) DEFAULT NULL COMMENT '创建者',
  `UpdateBy` int(4) DEFAULT NULL COMMENT '修改者',
  `Gender` tinyint(4) DEFAULT NULL COMMENT '性别（0：男，1：女）',
  `Phone` varchar(11) DEFAULT NULL COMMENT '手机',
  `Email` varchar(30) DEFAULT NULL COMMENT '邮箱',
  `Remark` varchar(50) DEFAULT NULL COMMENT '备注',
  `HeadShot` varchar(50) DEFAULT NULL COMMENT '头像',
  PRIMARY KEY (`Id`)
) ENGINE=InnoDB AUTO_INCREMENT=45 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of t_user
-- ----------------------------
INSERT INTO `t_user` VALUES ('', 'admin', '超级管理员', 'e10adc3949ba59abbe56e057f20f883e', '', '', '0001-01-01 00:00:00', '2018-05-12 21:47:34', '', '', '', '', '[e-mail]', null, '/Upload/img/mmexport1510485826478[1]_看图王_2.jpg');
INSERT INTO `t_user` VALUES ('', 'test', 'test', 'e10adc3949ba59abbe56e057f20f883e', '', '', '2018-04-26 10:35:56', '2018-04-29 10:36:12', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 08:42:00', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 08:57:05', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 08:58:31', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 08:59:22', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', 'a', 'a', null, '', '', '2018-04-29 09:04:29', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', 't', 't', null, '', '', '2018-04-29 09:05:24', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', 'e10adc3949ba59abbe56e057f20f883e', '', '', '2018-04-29 09:16:44', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 09:17:29', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 09:18:57', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', 'E10ADC3949BA59ABBE56E057F20F883E', '', '', '2018-04-29 09:19:55', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 09:32:53', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', 'e10adc3949ba59abbe56e057f20f883e', '', '', '2018-04-29 09:33:13', '0001-01-01 00:00:00', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '2018-04-29 09:33:30', '2018-04-29 17:29:18', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', 'e10adc3949ba59abbe56e057f20f883e', '', '', '2018-04-29 09:40:58', '2018-04-29 13:10:08', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '0001-01-01 00:00:00', '2018-04-29 10:32:02', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '0001-01-01 00:00:00', '2018-04-29 10:08:50', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '0001-01-01 00:00:00', '2018-04-29 10:08:09', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '0001-01-01 00:00:00', '2018-04-29 10:31:36', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '0001-01-01 00:00:00', '2018-04-29 10:07:36', '', null, null, null, null, null, null);
INSERT INTO `t_user` VALUES ('', '', '', null, '', '', '0001-01-01 00:00:00', '2018-04-29 10:06:52', '', null, null, null, null, null, null);

3、对项目进行配置。我对配置项进行了详实的注释，如有不懂的，自己翻阅相关文档。

application.yml

spring:
  profiles:
    active: dev

application-dev.yml

server:
  port: 8080
spring:
  thymeleaf:
    cache: false #开发阶段，建议关闭Thymeleaf的缓存
    mode: LEGACYHTML5 #使用遗留的html5以去掉对html标签的校验
  datasource:
    name: demo
    url: jdbc:mysql://127.0.0.1:3306/RightControl?useSSL=false&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true
    username: root
    password: yujie
    # 使用druid数据源
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    filters: stat
    maxActive: 20 # 最大活跃数
    initialSize: 5 # 初始化数量
    maxWait: 60000
    minIdle: 1
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: select 'x'
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true
    maxOpenPreparedStatements: 20

mybatis:
  mapper-locations: classpath:mapping/*.xml  #Locations of Mapper xml config file.
  type-aliases-package: com.yujie.dao  #Packages to search for type aliases. (Package delimiters are ",; \t\n")

#pagehelper分页插件
pagehelper:
    helperDialect: mysql
    reasonable: true #pageNum<=0 时会查询第一页， pageNum>pages（超过总数时），会查询最后一页
    supportMethodsArguments: true #支持通过 Mapper 接口参数来传递分页参数
    #用于从对象中根据属性名取值，可以配置 pageNum,pageSize,count,pageSizeZero,reasonable。
    #不配置映射的用默认值，默认值为pageNum=pageNum;pageSize=pageSize;count=countSql;reasonable=reasonable;pageSizeZero=pageSizeZero
    params: count=countSql

4、自动生成mybatis相关的配置，具体如何生成这个可以参考我前面的文章。从.Net到Java学习第三篇——spring boot+mybatis+mysql

在自动生成好的mybatis配置中，我们还需要自己扩展一个方法CheckLogin用于校验用户名和密码是否正确。

我们首先修改UserModelMapper类，需要注意的是checkLogin方法中的参数前面一定要记得添加@Param，因为mybatis很坑的一个地方，是对于单个参数，你不需要添加@Param，对于多个参数你必须要添加@Param，否则会报错，提示找不到参数。

@Component
public interface UserModelMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(UserModel record);

    int insertSelective(UserModel record);

    UserModel selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(UserModel record);

    int updateByPrimaryKey(UserModel record);
    //add
    UserModel checkLogin(@Param("username") String username,@Param("password") String password);
}

接下来修改UserModelMapper.xml，在其中添加一个checkLogin

  <sql id="Base_Column_List">
  Id, UserName, RealName, PassWord, RoleId, Status, CreateOn, UpdateOn, CreateBy, UpdateBy, 
  Gender, Phone, Email, Remark, HeadShot
</sql>

<select id="checkLogin" resultMap="BaseResultMap">
    select
    <include refid="Base_Column_List" />
    from t_user
    where username=#{username,jdbcType=VARCHAR} and password=#{password,jdbcType=VARCHAR}
  </select>

5、增加验证码的实现类ValidateCode

package com.yujie.util;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 * 验证码生成器
 *
 * @author
 */
public class ValidateCode {
    // 图片的宽度。
    private int width = 160;
    // 图片的高度。
    private int height = 40;
    // 验证码字符个数
    private int codeCount = 5;
    // 验证码干扰线数
    private int lineCount = 150;
    // 验证码
    private String code = null;
    // 验证码图片Buffer
    private BufferedImage buffImg = null;

    // 验证码范围,去掉0(数字)和O(拼音)容易混淆的(小写的1和L也可以去掉,大写不用了)
    private char[] codeSequence = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
            'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
            'X', 'Y', 'Z', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

    /**
     * 默认构造函数,设置默认参数
     */
    public ValidateCode() {
        this.createCode();
    }

    /**
     * @param width  图片宽
     * @param height 图片高
     */
    public ValidateCode(int width, int height) {
        this.width = width;
        this.height = height;
        this.createCode();
    }

    /**
     * @param width     图片宽
     * @param height    图片高
     * @param codeCount 字符个数
     * @param lineCount 干扰线条数
     */
    public ValidateCode(int width, int height, int codeCount, int lineCount) {
        this.width = width;
        this.height = height;
        this.codeCount = codeCount;
        this.lineCount = lineCount;
        this.createCode();
    }

    public void createCode() {
        int x = 0, fontHeight = 0, codeY = 0;
        int red = 0, green = 0, blue = 0;

        x = width / (codeCount + 2);//每个字符的宽度(左右各空出一个字符)
        fontHeight = height - 2;//字体的高度
        codeY = height - 4;

        // 图像buffer
        buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = buffImg.createGraphics();
        // 生成随机数
        Random random = new Random();
        // 将图像填充为白色
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, width, height);
        // 创建字体,可以修改为其它的
        Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);
//        Font font = new Font("Times New Roman", Font.ROMAN_BASELINE, fontHeight);
        g.setFont(font);

        for (int i = 0; i < lineCount; i++) {
            // 设置随机开始和结束坐标
            int xs = random.nextInt(width);//x坐标开始
            int ys = random.nextInt(height);//y坐标开始
            int xe = xs + random.nextInt(width / 8);//x坐标结束
            int ye = ys + random.nextInt(height / 8);//y坐标结束

            // 产生随机的颜色值，让输出的每个干扰线的颜色值都将不同。
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            g.setColor(new Color(red, green, blue));
            g.drawLine(xs, ys, xe, ye);
        }

        // randomCode记录随机产生的验证码
        StringBuffer randomCode = new StringBuffer();
        // 随机产生codeCount个字符的验证码。
        for (int i = 0; i < codeCount; i++) {
            String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
            // 产生随机的颜色值，让输出的每个字符的颜色值都将不同。
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            g.setColor(new Color(red, green, blue));
            g.drawString(strRand, (i + 1) * x, codeY);
            // 将产生的四个随机数组合在一起。
            randomCode.append(strRand);
        }
        // 将四位数字的验证码保存到Session中。
        code = randomCode.toString();
    }

    public void write(String path) throws IOException {
        OutputStream sos = new FileOutputStream(path);
        this.write(sos);
    }

    public void write(OutputStream sos) throws IOException {
        ImageIO.write(buffImg, "png", sos);
        sos.close();
    }

    public BufferedImage getBuffImg() {
        return buffImg;
    }

    public String getCode() {
        return code.toLowerCase();
    }
}

这里需要注意的是假设我们要让验证码大小写不敏感，那么需要code.toLowerCase();对生成的验证码字符串进行转换。

6、新增一个ajax对象类AjaxResult

package com.yujie.util;

public class AjaxResult {
    /// <summary>
    /// 操作结果类型
    /// </summary>
    public Object state;
    /// <summary>
    /// 获取 消息内容
    public String message;
    /// <summary>
    /// 获取 返回数据
    /// </summary>
    public Object data;

    public Object getState() {
        return state;
    }

    public void setState(Object state) {
        this.state = state;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
    public static AjaxResult ok(String msg){
        AjaxResult model=new AjaxResult();
        model.setMessage(msg);
        model.state="success";
        return model;
    }
    public static AjaxResult error(String msg){
        AjaxResult model=new AjaxResult();
        model.setMessage(msg);
        model.state="fail";
        return model;
    }
}

7、添加控制器LoginController

@Controller
@RequestMapping("/login")
public class LoginController extends BaseController {
    @Autowired
    IUserService userService;
    @GetMapping("")
    public String login(Model model){
        model.addAttribute("title","后台管理系统");
        return render("login");
    }
    @ResponseBody
    @PostMapping("/CheckLogin")
    public AjaxResult CheckLogin(@RequestParam String username, @RequestParam String password, @RequestParam String code,
                                 HttpServletRequest request,
                                 HttpServletResponse response){
        Object objCode=request.getSession().getAttribute("code");
        String _code=objCode.toString().toLowerCase();
        if(!code.equals(_code)){
           return AjaxResult.error("验证码错误，请重新输入！");
        }
        UserModel userModel=userService.CheckLogin(username,password);
        if(userModel==null) {
            return AjaxResult.error("用户名或密码，请重新输入！");
        }else {
            request.getSession().setAttribute("userinfo",userModel);
            return AjaxResult.ok("成功");
        }
    }
    /**
     * 响应验证码页面
     * @return
     */
    @GetMapping(value="/GetAuthCode")
    public String validateCode(HttpServletRequest request, HttpServletResponse response) throws Exception{
        // 设置响应的类型格式为图片格式
        response.setContentType("image/jpeg");
        //禁止图像缓存。
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        HttpSession session = request.getSession();

        ValidateCode vCode = new ValidateCode(120,40,4,100);
        session.setAttribute("code", vCode.getCode());
        vCode.write(response.getOutputStream());
        return null;
    }
}

考虑到一些公共的信息，我添加了一个控制器的父类BaseController

public abstract class BaseController {
    public static String THEME = "admin";
    public BaseController title(HttpServletRequest request, String title) {
        request.setAttribute("title", title);
        return this;
    }
    /**
     * 主页的页面主题
     * @param viewName
     * @return
     */
    public String render(String viewName) {
        return THEME + "/" + viewName;
    }
    public String render_404() {
        return "comm/error_404";
    }
    protected WebSiteModel GetWebSiteModel(){
        WebSiteModel model=new WebSiteModel();
        model.setSiteName("网站后台管理系统");
        return model;
    }
    protected UserModel GetUserInfo(HttpServletRequest request){
        HttpSession session = request.getSession();
        if (null == session) {
            return null;
        }
        return (UserModel)session.getAttribute("userinfo");
    }
}

8、实现服务层，添加IUserService接口，接口的命名我沿用C#的规范首字母用I

public interface IUserService extends IBaseService<UserModel> {
    UserModel CheckLogin(String username, String password);
}

9、添加接口的实现类UserService

package com.yujie.service.impl;

import com.yujie.dao.UserModelMapper;
import com.yujie.model.UserModel;
import com.yujie.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserService implements IUserService {
    @Autowired
    UserModelMapper userModelMapper;
    @Override
    public UserModel CheckLogin(String username, String password) {
        return userModelMapper.checkLogin(username,password);
    }
}

接触java的时间不长，发现一个很有意思的想象，不知道是否是写java默认约定，那就是实现类都是单独用一个叫做impl的包封装。

10、剩下的就是View了，

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8"/>
    <title>快速开发平台</title>
    <link th:href="@{/fonts/iconfont.css}" rel="stylesheet" />
    <link th:href="@{/css/login.css}" rel="stylesheet" />
    <script th:src="@{/js/jquery-1.10.2.min.js}"></script>
    <script th:src="@{/js/jquery.cookie.js}"></script>
    <script th:src="@{/js/jquery.md5.js}"></script>
    <!--[if lte IE 8]>
    <div id="errorie"><div>您还在使用老掉牙的IE，正常使用系统前请升级您的浏览器到 IE8以上版本 <a target="_blank" href="http://windows.microsoft.com/zh-cn/internet-explorer/ie-8-worldwide-languages">点击升级</a>&nbsp;&nbsp;强烈建议您更改换浏览器：<a href="http://down.tech.sina.com.cn/content/40975.html" target="_blank">谷歌 Chrome</a></div></div>
    <![endif]-->
</head>
<body>
<div style="position: absolute; z-index: 999; top: 20px; left: 20px; color: #fff; font-size: 13px; line-height: 22px;">
    用户名 admin，密码 123456，请勿在系统内发表不文明信息
</div>
<div class="wrapper">
    <div class="container">
        <div class="logo">
            <i class="iconfont icon-ditu"></i>
            <h1><span>登录</span><span th:text="${title}" th:remove="tag"></span></h1>
        </div>
        <form class="form">
            <div class="row">
                <input id="txt_account" type="text" placeholder="用户名">
                <i class="fa fa-user"></i>
            </div>
            <div class="row">
                <input id="txt_password" type="password" placeholder="登录密码">
                <i class="fa fa-key"></i>
            </div>
            <div class="row">
                <input id="txt_code" maxlength="4" type="text" placeholder="验证码" style="width: 190px; float: left;">
                <div style="width: 110px; float: right; padding-top: 14px; padding-left: 14px;">
                    看不清？<a id="switchCode" href="javascript:void();" style="text-decoration: none;">换一张</a>
                    <img id="imgcode" class="authcode" th:src="@{/login/GetAuthCode}" width="80" height="25" />
                </div>
            </div>
            <div class="row">
                <button id="login_button" type="button"><span>登录</span></button>
            </div>
            <div class="row">
            </div>
        </form>
        <div class="login_tips"></div>
    </div>
    <ul class="bg-bubbles">
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
</div>
<div class="copyright">
    <a href="@ViewBag.SiteDomain" style="text-decoration:none;color:#fff;" target="_blank">@ViewBag.CopyRight 开发团队出品</a>
    <br>
    适用浏览器：IE8以上、360、FireFox、Chrome、Safari、Opera、傲游、搜狗、世界之窗.
</div>
<script type="text/javascript">
    (function ($) {
        $.login = {
            formMessage: function (msg) {
                $('.login_tips').find('.tips_msg').remove();
                $('.login_tips').append('<div class="tips_msg"><i class="fa fa-question-circle"></i>' + msg + '</div>');
            },
            loginClick: function () {
                var $username = $("#txt_account");
                var $password = $("#txt_password");
                var $code = $("#txt_code");
                if ($username.val() == "") {
                    $username.focus();
                    $.login.formMessage('请输入用户名');
                    return false;
                } else if ($password.val() == "") {
                    $password.focus();
                    $.login.formMessage('请输入登录密码。');
                    return false;
                } else if ($code.val() == "") {
                    $code.focus();
                    $.login.formMessage('请输入验证码。');
                    return false;
                } else {
                    $("#login_button").attr('disabled', 'disabled').find('span').html("loading...");
                    $.ajax({
                        url: "/login/CheckLogin",
                        data: { username: $.trim($username.val()), password: $.md5($.trim($password.val())), code: $.trim($code.val()) },
                        type: "post",
                        dataType: "json",
                        success: function (data) {
                            if (data.state == "success") {
                                $("#login_button").find('span').html("登录成功，正在跳转...");
                                window.setTimeout(function () {
                                    window.location.href = "/home";
                                }, 500);
                            } else {
                                $("#login_button").removeAttr('disabled').find('span').html("登录");
                                $("#switchCode").trigger("click");
                                $code.val('');
                                $.login.formMessage(data.message);
                            }
                        }
                    });
                }
            },
            init: function () {
                $('.wrapper').height($(window).height());
                $(".container").css("margin-top", ($(window).height() - $(".container").height()) / 2 - 50);
                $(window).resize(function (e) {
                    $('.wrapper').height($(window).height());
                    $(".container").css("margin-top", ($(window).height() - $(".container").height()) / 2 - 50);
                });
                $("#switchCode").click(function () {
                    $("#imgcode").attr("src", "/login/GetAuthCode?time=" + Math.random());
                });
                var login_error = top.$.cookie('nfine_login_error');
                if (login_error != null) {
                    switch (login_error) {
                        case "overdue":
                            $.login.formMessage("系统登录已超时,请重新登录");
                            break;
                        case "OnLine":
                            $.login.formMessage("您的帐号已在其它地方登录,请重新登录");
                            break;
                        case "-1":
                            $.login.formMessage("系统未知错误,请重新登录");
                            break;
                    }
                    top.$.cookie('nfine_login_error', '', { path: "/", expires: -1 });
                }
                $("#login_button").click(function () {
                    $.login.loginClick();
                });
                document.onkeydown = function (e) {
                    if (!e) e = window.event;
                    if ((e.keyCode || e.which) == 13) {
                        document.getElementById("login_button").focus();
                        document.getElementById("login_button").click();
                    }
                }
            }
        };
        $(function () {
            $.login.init();
        });
    })(jQuery);
</script>
</body>
</html>

templates下添加admin目录，admin目录下，添加login.html页面。

这样登录就已经实现，然后我们还有一个权限拦截器啊。Java中通过实现HandlerInterceptor这个接口来进行过拦截功能，其实也可以通过继承另一个类来实现同样的功能，不过建议使用接口。具体类名，我一下子想不起来啦！O(∩_∩)O哈哈~

新建类BaseInterceptor

package com.yujie.filter;

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.logging.Logger;
@Component
public class BaseInterceptor implements HandlerInterceptor {
    private static final Logger logger = Logger.getLogger("BaseInterceptor");
    private static final String loginUrl="/login";
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        //1、请求到登录页面 放行
        if(request.getServletPath().startsWith(loginUrl)) {
            return true;
        }

        //2、TODO 比如退出、首页等页面无需登录，即此处要放行 允许游客的请求

        //3、如果用户已经登录 放行
        if(request.getSession().getAttribute("userinfo") != null) {
            //更好的实现方式的使用cookie
            return true;
        }
        //4、非法请求 即这些请求需要登录后才能访问
        //重定向到登录页面
        response.sendRedirect(request.getContextPath() + loginUrl);
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }
}

然后我们要新建一个配置类WebMvcConfig，将这个创建的拦截器添加进来。

@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
    @Resource
    private BaseInterceptor baseInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // addPathPatterns 用于添加拦截规则, 这里假设拦截 /url 后面的全部链接
        // excludePathPatterns 用户排除拦截
        registry.addInterceptor(baseInterceptor).addPathPatterns("/**");
    }

    /**
     * 添加静态资源文件，外部可以直接访问地址
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/upload/**").addResourceLocations("upload/");
        super.addResourceHandlers(registry);
    }
}

这样就一切OK了，接下来看下演示效果。

代码结构图：

感觉有.net基础的话，进行java开发还是蛮简单的。