day03【后台】管理员维护

浅浅的花香味﹌ 2022-12-08 14:26 206阅读 0赞

# day03【后台】管理员维护 #

## 1、分页 ##

### 1.1、思路 ###

![image-20200919184108150][]

### 1.2、导入依赖 ###

*  在`component`工程中导入`PageHelper`的依赖

<dependency>
      <groupId>com.github.pagehelper</groupId>
      <artifactId>pagehelper</artifactId>
    </dependency>

### 1.3、配置 PageHelper ###

*  `Spring`的配置文件中，在 `SqlSessionFactoryBean` 中配置 `PageHelper` 插件

![image-20200611144219761][]

<bean id="sqlSessionFactoryBean"
          class="org.mybatis.spring.SqlSessionFactoryBean">
      
      <property name="dataSource" ref="dataSource" />
      
      <property name="configLocation"
                value="classpath:mybatis-config.xml" />
      
      <property name="mapperLocations"
                value="classpath:mybatis/mapper/*Mapper.xml" />
    
      
      <property name="plugins">
        <array>
          
          <bean class="com.github.pagehelper.PageHelper">
            <property name="properties">
              <props>
                
                <prop key="dialect">mysql</prop>
                
                <prop key="reasonable">true</prop>
              </props>
            </property>
          </bean>
        </array>
      </property>
    </bean>

### 1.4、编写Mapper ###

*  在`AdminMapper`接口中添加`selectAdminByKeyword`方法声明，该方法根据关键字搜索用户

![image-20200611145258780][]

List<Admin> selectAdminByKeyword(String keyword);

*  在`AdminMapper.xml`中添加`selectAdminByKeyword`方法对应的查询`SQL`语句

![image-20200611145813062][]

<select id="selectAdminByKeyword" resultMap="BaseResultMap">
      select id, login_acct, user_pswd, user_name, email, create_time
      from t_admin
      where
      login_acct like concat("%",#{keyword},"%") or
      user_name like concat("%",#{keyword},"%") or
      email like concat("%",#{keyword},"%")
    </select>

### 1.5、编写Service ###

*  在`AdminService.java`接口下添加`getPageInfo`方法，用于查询管理员分页数据

![image-20200611150701238][]

PageInfo<Admin> getPageInfo(String keyword, Integer pageNum, Integer pageSize);

*  在`AdminServiceImpl.java`中实现上述方法

![image-20200611150826737][]

@Override
    public PageInfo<Admin> getPageInfo(String keyword, Integer pageNum, Integer pageSize) {
        		
      // 1.调用PageHelper的静态方法开启分页功能
      // 这里充分体现了PageHelper的“非侵入式”设计：原本要做的查询不必有任何修改
      PageHelper.startPage(pageNum, pageSize);
    
      // 2.执行查询
      List<Admin> list = adminMapper.selectAdminByKeyword(keyword);
    
      // 3.封装到PageInfo对象中
      return new PageInfo<>(list);
    }

### 1.6、编写Handler ###

*  在`AdminHandler`调用`AdminService`获取数据

![image-20200611151604944][]

@RequestMapping("/admin/get/page.html")
    public String getPageInfo(			
      // 使用@RequestParam注解的defaultValue属性，指定默认值，在请求中没有携带对应参数时使用默认值
      // keyword默认值使用空字符串，和SQL语句配合实现两种情况适配
      @RequestParam(value="keyword", defaultValue="") String keyword,
    
      // pageNum默认值使用1
      @RequestParam(value="pageNum", defaultValue="1") Integer pageNum,
    
      // pageSize默认值使用5
      @RequestParam(value="pageSize", defaultValue="5") Integer pageSize,
    
      ModelMap modelMap			
    ) {
        		
      // 调用Service方法获取PageInfo对象
      PageInfo<Admin> pageInfo = adminService.getPageInfo(keyword, pageNum, pageSize);
    
      // 将PageInfo对象存入模型
      modelMap.addAttribute(CrowdConstant.ATTR_NAME_PAGE_INFO, pageInfo);
    
      return "admin-page";
    }

### 1.7、编写页面 ###

*  在`component`工程的`pom`文件中引入`JSTL`标签库依赖

![image-20200611152912242][]

<dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
    </dependency>

*  在`include-sidebar.jsp`页面中添加跳转地址

![image-20200611153454410][]

*  在`admin-page.jsp`页面中取出数据并显示

![image-20200611153605288][]

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
    <!DOCTYPE html>
    <html lang="zh-CN">
    <%@include file="/WEB-INF/include-head.jsp"%>
    
    <body>
    	<%@ include file="/WEB-INF/include-nav.jsp"%>
    	<div class="container-fluid">
    		<div class="row">
    			<%@ include file="/WEB-INF/include-sidebar.jsp"%>
    			<div class="col-sm-9 col-sm-offset-3 col-md-10 col-md-offset-2 main">
    				<div class="panel panel-default">
    					<div class="panel-heading">
    						<h3 class="panel-title">
    							<i class="glyphicon glyphicon-th"></i> 数据列表
    						</h3>
    					</div>
    					<div class="panel-body">
    						<form class="form-inline" role="form" style="float: left;">
    							<div class="form-group has-feedback">
    								<div class="input-group">
    									<div class="input-group-addon">查询条件</div>
    									<input class="form-control has-success" type="text"
    										placeholder="请输入查询条件">
    								</div>
    							</div>
    							<button type="button" class="btn btn-warning">
    								<i class="glyphicon glyphicon-search"></i> 查询
    							</button>
    						</form>
    						<button type="button" class="btn btn-danger"
    							style="float: right; margin-left: 10px;">
    							<i class=" glyphicon glyphicon-remove"></i> 删除
    						</button>
    						<button type="button" class="btn btn-primary"
    							style="float: right;" onclick="window.location.href='add.html'">
    							<i class="glyphicon glyphicon-plus"></i> 新增
    						</button>
    						<br>
    						<hr style="clear: both;">
    						<div class="table-responsive">
    							<table class="table  table-bordered">
    								<thead>
    									<tr>
    										<th width="30">#</th>
    										<th width="30"><input type="checkbox"></th>
    										<th>账号</th>
    										<th>名称</th>
    										<th>邮箱地址</th>
    										<th width="100">操作</th>
    									</tr>
    								</thead>
    								<tbody>
    									<c:if test="${empty requestScope.pageInfo.list }">
    										<tr>
    											<td colspan="6" align="center">抱歉！没有查询到您要的数据！</td>
    										</tr>
    									</c:if>
    									<c:if test="${!empty requestScope.pageInfo.list }">
    										<c:forEach items="${requestScope.pageInfo.list }" var="admin"
    											varStatus="myStatus">
    											<tr>
    												<td>${myStatus.count }</td>
    												<td><input type="checkbox"></td>
    												<td>${admin.loginAcct }</td>
    												<td>${admin.userName }</td>
    												<td>${admin.email }</td>
    												<td>
    													<button type="button" class="btn btn-success btn-xs">
    														<i class=" glyphicon glyphicon-check"></i>
    													</button>
    													<button type="button" class="btn btn-primary btn-xs">
    														<i class=" glyphicon glyphicon-pencil"></i>
    													</button>
    													<button type="button" class="btn btn-danger btn-xs">
    														<i class=" glyphicon glyphicon-remove"></i>
    													</button>
    												</td>
    											</tr>
    										</c:forEach>
    									</c:if>
    								</tbody>
    								<tfoot>
    									<tr>
    										<td colspan="6" align="center">
    											<ul class="pagination">
    												<li class="disabled"><a href="#">上一页</a></li>
    												<li class="active"><a href="#">1 <span
    														class="sr-only">(current)</span></a></li>
    												<li><a href="#">2</a></li>
    												<li><a href="#">3</a></li>
    												<li><a href="#">4</a></li>
    												<li><a href="#">5</a></li>
    												<li><a href="#">下一页</a></li>
    											</ul>
    										</td>
    									</tr>
    								</tfoot>
    							</table>
    						</div>
    					</div>
    				</div>
    			</div>
    		</div>
    	</div>
    </body>
    </html>

### 1.8、测试 ###

*  测试成功

![image-20200611154114134][]

### 1.9、Tips ###

*  以上部分均为`day02`内容，以下部分才是`day03`内容

## 2、分页导航条 ##

### 2.1、导入资源 ###

*  在`webapp`目录下引入`Pagination`所需要的`js`和`css`库

![image-20200611161028488][]

### 2.2、在需要的页面引入资源 ###

*  在`admin-page.jsp`页面引入相关的资源，由于`<%@include%>`引入了`jQuery`，将资源的引入`jQuery`的后面

![image-20200611161624583][]

<%@include file="/WEB-INF/include-head.jsp"%>
    <link rel="stylesheet" href="css/pagination.css" />
    <script type="text/javascript" src="jquery/jquery.pagination.js"></script>

### 2.3、加入分页条 ###

*  加入`Pagination`：一个`div`即可

![image-20200611161839286][]

### 2.4、使用Pagination ###

*  在`admin-page.jsp`页面下添加如下代码，使用`Pagination`生成分页条

![image-20200611164803787][]

### 2.5、修复Pagination Bug ###

*  `Bug`产生原因：请求页面 --> 绘制分页条 --> 调用回调函数 --> 页面跳转 --> 请求页面 --> 绘制分页条 --> 调用回调函数 --> 页面跳转 … 就这样陷入了陷入死循环

![image-20200611165810832][]

### 2.6、测试 ###

*  成了~

![image-20200611165612747][]

## 3、关键词查询 ##

### 3.1、修改表单 ###

*  修改`admin-page.jsp`中查询表单
    
     *  表单提交`URI`为`admin/get/page.html`
     *  `<input name="keyword"/>`：输入框名称需要与`Handler`参数名称对应
     *  `<button type="submit">`：`submit`按钮用于提交表单

### 3.2、翻页带上关键词查询条件 ###

*  由于搜索关键词之后，并没有进行重定向操作，所以都是同一次请求，直接从请求参数中取出搜索关键词即可

![image-20200611192707341][]

### 3.3、测试 ###

*  乌拉~

![image-20200611192206287][]

## 4、单条删除 ##

### 4.1、提交删除请求 ###

*  在`admin-page.jsp`页面，添加提交删除请求的`a`标签，删除管理员时，除了要携带管理员`Id`：`id`，还需要附带当前页码：`pageNum`，当前查询关键词：`keyword`

![image-20200611212429605][]

### 4.2、编写业务逻辑 ###

#### 4.2.1、Handler代码 ####

*  在`AdminHandler`中添加`remove`方法，从路径变量中取出所需的参数即可

![image-20200611212549366][]

@RequestMapping("/admin/remove/{adminId}/{pageNum}/{keyword}.html")
    public String remove(
      @PathVariable("adminId") Integer adminId,
      @PathVariable("pageNum") Integer pageNum,
      @PathVariable("keyword") String keyword
    ) {
        		
      // 执行删除
      adminService.remove(adminId);
    
      // 页面跳转：回到分页页面		
      // 尝试方案1：直接转发到admin-page.jsp会无法显示分页数据
      // return "admin-page";
    
      // 尝试方案2：转发到/admin/get/page.html地址，一旦刷新页面会重复执行删除浪费性能
      // return "forward:/admin/get/page.html";
    
      // 尝试方案3：重定向到/admin/get/page.html地址
      // 同时为了保持原本所在的页面和查询关键词再附加pageNum和keyword两个请求参数
      return "redirect:/admin/get/page.html?pageNum="+pageNum+"&keyword="+keyword;
    }

#### 4.2.2、Service代码 ####

*  在`Service`接口中声明`remove`方法，在`Service`实现类中实现`remove`方法

![image-20200611212704950][]

@Override
    public void remove(Integer adminId) {
        
      adminMapper.deleteByPrimaryKey(adminId);	
    }

### 4.3、莫名其妙的Bug ###

#### 4.3.1、Bug描述 ####

*  莫名其妙会执行删除管理员的操作，但是我并没有执行删除操作。。。

#### 4.3.2、Bug排除 ####

*  特么居然是因为`FasterChrome`插件，只要你鼠标悬停有超链接的标签上，这个插件会预先发送请求给服务器，并接受服务器的请求，以缓存方式保存，等到你点击时，便会直接从缓存中取出数据，让你纵享丝滑~~~

![image-20200619104904312][]

*  恰好删除按钮并没有写`JS`代码，只要鼠标悬停在删除按钮上，便会触发删除请求，我特么的，终于知道为什么`t_admin`表中的数据莫名其妙地消失了。。。

![image-20200619105637979][]

*  程序在断点处停住。。。

![image-20200619105642629][]

#### 4.3.3、解决办法 ####

*  把`FasterChrome`插件禁用掉

![image-20200619105807912][]

## 5、新增 ##

### 5.1、思路 ###

![image-20200919184738292][]

### 5.2、设置唯一约束 ###

*  将`login_acct`字段设置为唯一约束

![image-20200611213658473][]

*  查看历史记录得到设置唯一约束的`SQL`语句

![image-20200611213821803][]

ALTER TABLE `project_crowd`.`t_admin` ADD UNIQUE INDEX (`login_acct`);

### 5.3、提交新增请求 ###

*  修改`admin-page.jsp`页面，添加提交新增请求的`a`标签

![image-20200611220431380][]

### 5.4、配置view-controller ###

*  由于点击`a`标签超链接后直接转发页面，无需其他操作，所以我们直接配置`view-controller`

![image-20200611220646143][]

<mvc:view-controller 
    	path="/admin/to/add/page.html" view-name="admin-add"/>

### 5.5、准备表单页面 ###

*  准备新增管理员表单页面`admin-add.jsp`
    
     *  表单提交地址为`admin/save.html`
     *  各个`input`标签的`name`属性值需要与`java bean`属性对应

![image-20200611220729015][]

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html lang="zh-CN">
    <%@include file="/WEB-INF/include-head.jsp"%>
    
    <body>
    	<%@ include file="/WEB-INF/include-nav.jsp"%>
    	<div class="container-fluid">
    		<div class="row">
    			<%@ include file="/WEB-INF/include-sidebar.jsp"%>
    			<div class="col-sm-9 col-sm-offset-3 col-md-10 col-md-offset-2 main">
    				<ol class="breadcrumb">
    					<li><a href="/admin/to/main/page.html">首页</a></li>
    					<li><a href="/admin/get/page.html">数据列表</a></li>
    					<li class="active">新增</li>
    				</ol>
    				<div class="panel panel-default">
    					<div class="panel-heading">
    						表单数据
    						<div style="float: right; cursor: pointer;" data-toggle="modal"
    							data-target="#myModal">
    							<i class="glyphicon glyphicon-question-sign"></i>
    						</div>
    					</div>
    					<div class="panel-body">
    						<form action="admin/save.html" method="post" role="form">
    							<p>${requestScope.exception.message }</p>
    							<div class="form-group">
    								<label for="exampleInputPassword1">登录账号</label> 
    								<input
    									name="loginAcct" type="text" class="form-control"
    									id="exampleInputPassword1" placeholder="请输入登录账号">
    							</div>
    							<div class="form-group">
    								<label for="exampleInputPassword1">登录密码</label> 
    								<input
    									name="userPswd" type="text" class="form-control"
    									id="exampleInputPassword1" placeholder="请输入登录密码">
    							</div>
    							<div class="form-group">
    								<label for="exampleInputPassword1">用户昵称</label> 
    								<input
    									name="userName" type="text" class="form-control"
    									id="exampleInputPassword1" placeholder="请输入用户名称">
    							</div>
    							<div class="form-group">
    								<label for="exampleInputEmail1">邮箱地址</label> 
    								<input type="email"
    									name="email" class="form-control" id="exampleInputEmail1"
    									placeholder="请输入邮箱地址">
    								<p class="help-block label label-warning">请输入合法的邮箱地址, 格式为：
    									xxxx@xxxx.com</p>
    							</div>
    							<button type="submit" class="btn btn-success">
    								<i class="glyphicon glyphicon-plus"></i> 新增
    							</button>
    							<button type="reset" class="btn btn-danger">
    								<i class="glyphicon glyphicon-refresh"></i> 重置
    							</button>
    						</form>
    					</div>
    				</div>
    			</div>
    		</div>
    	</div>
    </body>
    </html>

### 5.6、Handler代码 ###

*  在`Handler`中保存新增的管理员之后，重定向至分页页面

![image-20200611221454231][]

@RequestMapping("/admin/save.html")
    public String save(Admin admin) {
        		
      adminService.saveAdmin(admin);	
      return "redirect:/admin/get/page.html?pageNum="+Integer.MAX_VALUE;
    }

### 5.7、用户名重复异常 ###

*  在`util`工程下创建`LoginAcctAlreadyInUseException`类，表示用户名重复异常

![image-20200611221549401][]

/**
     * 保存或更新Admin时如果检测到登录账号重复抛出这个异常
     * @author Lenovo
     *
     */
    public class LoginAcctAlreadyInUseException extends RuntimeException {
        
    
    	private static final long serialVersionUID = 1L;
    
    	public LoginAcctAlreadyInUseException() {
        
    		super();
    	}
    
    	public LoginAcctAlreadyInUseException(String message, Throwable cause, boolean enableSuppression,
    			boolean writableStackTrace) {
        
    		super(message, cause, enableSuppression, writableStackTrace);
    	}
    
    	public LoginAcctAlreadyInUseException(String message, Throwable cause) {
        
    		super(message, cause);
    	}
    
    	public LoginAcctAlreadyInUseException(String message) {
        
    		super(message);
    	}
    
    	public LoginAcctAlreadyInUseException(Throwable cause) {
        
    		super(cause);
    	}
    
    }

### 5.8、Service代码 ###

*  在`Service`中实现上述`Handler`中调用的方法
    
     *  将管理员密码加密存储
     *  设置管理员创建时间
     *  如果`login_acct`键重复，则抛出异常

![image-20200611221703001][]

private Logger logger = LoggerFactory.getLogger(AdminServiceImpl.class);
    
    @Override
    public void saveAdmin(Admin admin) {
        	
      // 1.密码加密
      String userPswd = admin.getUserPswd();
      userPswd = CrowdUtil.md5(userPswd);
      admin.setUserPswd(userPswd);
    
      // 2.生成创建时间
      Date date = new Date();
      SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
      String createTime = format.format(date);
      admin.setCreateTime(createTime);
    
      // 3.执行保存
      try {
        
        adminMapper.insert(admin);
      } catch (Exception e) {
        
        e.printStackTrace();			
        logger.info("异常全类名="+e.getClass().getName());			
        if(e instanceof DuplicateKeyException) {
        
          throw new LoginAcctAlreadyInUseException(CrowdConstant.MESSAGE_LOGIN_ACCT_ALREADY_IN_USE);
        }
      }		
    }

### 5.9、统一处理异常 ###

*  在`CrowdExceptionResolver`配置类中统一处理`LoginAcctAlreadyInUseException`类型的异常

![image-20200611221926174][]

@ExceptionHandler(value = LoginAcctAlreadyInUseException.class)
    public ModelAndView resolveLoginAcctAlreadyInUseException(
      LoginAcctAlreadyInUseException exception,
      HttpServletRequest request,
      HttpServletResponse response
    ) throws IOException {
        	
      String viewName = "admin-add";		
      return commonResolve(viewName, exception, request, response);
    }
    
    // @ExceptionHandler将一个具体的异常类型和一个方法关联起来
    private ModelAndView commonResolve(
      // 异常处理完成后要去的页面
      String viewName,
      // 实际捕获到的异常类型
      Exception exception,
      // 当前请求对象
      HttpServletRequest request,
      // 当前响应对象
      HttpServletResponse response
    ) throws IOException {
        
      // 1.判断当前请求类型
      boolean judgeResult = CrowdUtil.judgeRequestType(request);
      // 2.如果是Ajax请求
      if (judgeResult) {
        
        // 3.创建ResultEntity对象
        ResultEntity<Object> resultEntity = ResultEntity.failed(exception.getMessage());
        // 4.创建Gson对象
        Gson gson = new Gson();
        // 5.将ResultEntity对象转换为JSON字符串
        String json = gson.toJson(resultEntity);
        // 6.将JSON字符串作为响应体返回给浏览器
        response.getWriter().write(json);
        // 7.由于上面已经通过原生的response对象返回了响应，所以不提供ModelAndView对象
        return null;
      }
      // 8.如果不是Ajax请求则创建ModelAndView对象
      ModelAndView modelAndView = new ModelAndView();
      // 9.将Exception对象存入模型
      modelAndView.addObject("exception", exception);
      // 10.设置对应的视图名称
      modelAndView.setViewName(viewName);
      // 11.返回modelAndView对象
      return modelAndView;
    }

### 5.10、测试 ###

*  添加成功

![image-20200611222407258][]

*  添加失败

![image-20200611222330699][]

## 6、更新 ##

### 6.1、思路 ###

![image-20200919184902637][]

### 6.2、提交更新请求 ###

*  修改`admin-page.jsp`页面，添加提交更新请求的`a`标签
    
     *  更新管理员信息需要管理员`Id`
     *  更新完成后回到分页页面需要：当前页面`pageNum`和搜索关键词`keyword`

![image-20200612101421105][]

### 6.3、查询管理员 ###

#### 6.3.1、Handler代码 ####

*  在`AdminHandler`中查询出`Admin`信息，并转发至`admin-edit.jsp`页面；由于是同一次请求，所以请求参数`pageNum`和`keyword`到更新`Admin`的时候再取出来使用

![image-20200612101744867][]

@RequestMapping("/admin/to/edit/page.html")
    public String toEditPage(
      @RequestParam("adminId") Integer adminId,
      ModelMap modelMap
    ) {
        		
      // 1.根据adminId查询Admin对象
      Admin admin = adminService.getAdminById(adminId);
    
      // 2.将Admin对象存入模型
      modelMap.addAttribute("admin", admin);
    
      return "admin-edit";
    }

#### 6.3.2、Service代码 ####

*  在`Service`中实现上述`Handler`中调用的方法

![image-20200612102330407][]

@Override
    public Admin getAdminById(Integer adminId) {
        
      return adminMapper.selectByPrimaryKey(adminId);
    }

### 6.4、表单回显 ###

*  添加`admin-edit.jsp`页面，用于表单回显，表单提交地址为`admin/update.html`

![image-20200612102437433][]

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html lang="zh-CN">
    <%@include file="/WEB-INF/include-head.jsp"%>
    
    <body>
    	<%@ include file="/WEB-INF/include-nav.jsp"%>
    	<div class="container-fluid">
    		<div class="row">
    			<%@ include file="/WEB-INF/include-sidebar.jsp"%>
    			<div class="col-sm-9 col-sm-offset-3 col-md-10 col-md-offset-2 main">
    				<ol class="breadcrumb">
    					<li><a href="/admin/to/main/page.html">首页</a></li>
    					<li><a href="/admin/get/page.html">数据列表</a></li>
    					<li class="active">更新</li>
    				</ol>
    				<div class="panel panel-default">
    					<div class="panel-heading">
    						表单数据
    						<div style="float: right; cursor: pointer;" data-toggle="modal"
    							data-target="#myModal">
    							<i class="glyphicon glyphicon-question-sign"></i>
    						</div>
    					</div>
    					<div class="panel-body">
    						<form action="admin/update.html" method="post" role="form">
    							<input type="hidden" name="id" value="${requestScope.admin.id }" />
    							<input type="hidden" name="pageNum" value="${param.pageNum }" />
    							<input type="hidden" name="keyword" value="${param.keyword }" />
    							<p>${requestScope.exception.message }</p>
    							<div class="form-group">
    								<label for="exampleInputPassword1">登录账号</label>
    								<input
    									name="loginAcct" 
    									value="${requestScope.admin.loginAcct }"
    									type="text" class="form-control"
    									id="exampleInputPassword1" placeholder="请输入登录账号">
    							</div>
    							<div class="form-group">
    								<label for="exampleInputPassword1">用户昵称</label>
    								<input
    									name="userName"
    									value="${requestScope.admin.userName }" 
    									type="text" class="form-control"
    									id="exampleInputPassword1" placeholder="请输入用户名称">
    							</div>
    							<div class="form-group">
    								<label for="exampleInputEmail1">邮箱地址</label>
    								<input type="email"
    									name="email" 
    									value="${requestScope.admin.email }" class="form-control" id="exampleInputEmail1"
    									placeholder="请输入邮箱地址">
    								<p class="help-block label label-warning">请输入合法的邮箱地址, 格式为：
    									xxxx@xxxx.com</p>
    							</div>
    							<button type="submit" class="btn btn-success">
    								<i class="glyphicon glyphicon-edit"></i> 更新
    							</button>
    							<button type="reset" class="btn btn-danger">
    								<i class="glyphicon glyphicon-refresh"></i> 重置
    							</button>
    						</form>
    					</div>
    				</div>
    			</div>
    		</div>
    	</div>
    </body>
    </html>

### 6.5、Handler代码：更新管理员 ###

#### 6.5.1、Handler代码 ####

*  在`AdminHandler`中更新`Admin`管理员的信息，并重定向至分页页面

![image-20200612101744867][]

@RequestMapping("/admin/update.html")
    public String update(Admin admin, @RequestParam("pageNum") Integer pageNum, @RequestParam("keyword") String keyword) {
        		
      adminService.update(admin);		
      return "redirect:/admin/get/page.html?pageNum="+pageNum+"&keyword="+keyword;
    }

#### 6.5.2、Service代码 ####

*  在`Service`中保存`Admin`信息，并且捕获唯一键约束异常

![image-20200612102330407][]

@Override
    public void update(Admin admin) {
        	
      // “Selective”表示有选择的更新，对于null值的字段不更新
      try {
        
        adminMapper.updateByPrimaryKeySelective(admin);
      } catch (Exception e) {
        
        e.printStackTrace();			
        logger.info("异常全类名="+e.getClass().getName());		
        if(e instanceof DuplicateKeyException) {
        
          throw new LoginAcctAlreadyInUseForUpdateException(CrowdConstant.MESSAGE_LOGIN_ACCT_ALREADY_IN_USE);
        }
      }
    }

### 6.6、异常处理 ###

#### 6.6.1、创建异常类 ####

*  在`util`工程添加`LoginAcctAlreadyInUseForUpdateException`类，该类表示更新`Admin`时，其`login_acct`字段不唯一，引发的异常

![image-20200612103500808][]

/**
     * 保存或更新Admin时如果检测到登录账号重复抛出这个异常
     * @author Lenovo
     *
     */
    public class LoginAcctAlreadyInUseForUpdateException extends RuntimeException {
        
    
    	private static final long serialVersionUID = 1L;
    
    	public LoginAcctAlreadyInUseForUpdateException() {
        
    		super();
    	}
    
    	public LoginAcctAlreadyInUseForUpdateException(String message, Throwable cause, boolean enableSuppression,
    			boolean writableStackTrace) {
        
    		super(message, cause, enableSuppression, writableStackTrace);
    	}
    
    	public LoginAcctAlreadyInUseForUpdateException(String message, Throwable cause) {
        
    		super(message, cause);
    	}
    
    	public LoginAcctAlreadyInUseForUpdateException(String message) {
        
    		super(message);
    	}
    
    	public LoginAcctAlreadyInUseForUpdateException(Throwable cause) {
        
    		super(cause);
    	}
    
    }

#### 6.6.2、处理异常 ####

*  在`CrowdExceptionResolver`配置类中统一处理`LoginAcctAlreadyInUseForUpdateException`类型的异常

![image-20200612103903537][]

@ExceptionHandler(value = LoginAcctAlreadyInUseForUpdateException.class)
    public ModelAndView resolveLoginAcctAlreadyInUseForUpdateException(
      LoginAcctAlreadyInUseForUpdateException exception,
      HttpServletRequest request,
      HttpServletResponse response
    ) throws IOException {
        	
      String viewName = "system-error";	
      return commonResolve(viewName, exception, request, response);
    }

### 6.7、测试 ###

*  更新成功

![image-20200612104317328][]

*  更新失败

![image-20200612104501829][]

## 7、Ajax加餐 ##

### 7.1、异步Ajax ###

*  添加`test.jsp`页面用于测试`Ajax`请求

![image-20200612150519969][]

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html lang="zh-CN">
    <%@include file="/WEB-INF/include-head.jsp"%>
    <script type="text/javascript">
    	$(function() {
         
    		$("#asyncBtn").click(function() {
         
    			console.log("ajax函数之前");
          $.ajax({
         
              "url" : "test/ajax/async.html",
              "type" : "post",
              "dataType" : "text",
              "async" : true, // 默认值
              "success" : function(response) {
         
                // success是接收到服务器端响应后执行
                console.log("ajax函数内部的success函数" + response);
              }
            });
    
    			// 在$.ajax()执行完成后执行，不等待success()函数
    			console.log("ajax函数之后");
    
    			/* 等待5s后，再执行function()定义的函数
    			setTimeout(function(){
    				console.log("ajax函数之后");
    			}, 5000); */
    		});
    	});
    </script>
    <body>
    	<%@ include file="/WEB-INF/include-nav.jsp"%>
    	<div class="container-fluid">
    		<div class="row">
    			<%@ include file="/WEB-INF/include-sidebar.jsp"%>
    			<div class="col-sm-9 col-sm-offset-3 col-md-10 col-md-offset-2 main">
    				<button id="asyncBtn">发送Ajax请求</button>
    			</div>
    		</div>
    	</div>
    </body>
    </html>

*  `Handler`代码

![image-20200612150649060][]

@ResponseBody
    @RequestMapping("/test/ajax/async.html")
    public String testAsync() throws InterruptedException {
        
    	Thread.sleep(5000);
    	return "success";
    }

*  测试结果：

![image-20200612151018040][]

![image-20200612150158032][]

### 7.2、同步Ajax ###

*  将`Ajax`请求修改为同步：`"async" : false`

<%@ page language="java" contentType="text/html; charset=UTF-8"
    	pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html lang="zh-CN">
    <%@include file="/WEB-INF/include-head.jsp"%>
    <script type="text/javascript">
    	$(function() {
         
    		$("#asyncBtn").click(function() {
         
    			console.log("ajax函数之前");
          
    			$.ajax({
         
    				"url" : "test/ajax/async.html",
    				"type" : "post",
    				"dataType" : "text",
    				"async" : false, // 关闭异步工作模型，使用同步方式工作。此时：所有操作在同一个线程内按顺序完成
    				"success" : function(response) {
         
    					// success是接收到服务器端响应后执行
    					console.log("ajax函数内部的success函数" + response);
    				}
    			});
    
    			// 在$.ajax()执行完成后执行，不等待success()函数
    			console.log("ajax函数之后");
    			/* setTimeout(function(){
    				
    			}, 5000); */
    		});
    	});
    </script>
    <body>
    	<%@ include file="/WEB-INF/include-nav.jsp"%>
    	<div class="container-fluid">
    		<div class="row">
    			<%@ include file="/WEB-INF/include-sidebar.jsp"%>
    			<div class="col-sm-9 col-sm-offset-3 col-md-10 col-md-offset-2 main">
    				<button id="asyncBtn">发送Ajax请求</button>
    			</div>
    		</div>
    	</div>
    </body>
    </html>

*  `Handler`代码不变，测试结果如下

![image-20200612151419394][]

[image-20200919184108150]: /images/20221123/d611801e9b734f2c8c8ddfa91708d309.png
[image-20200611144219761]: /images/20221123/82bd5e0f377d43398aac73b85081f33e.png
[image-20200611145258780]: /images/20221123/19de3b14d8d54ef38a3a35142e2d96d7.png
[image-20200611145813062]: /images/20221123/3ea27cd864444352b8828b5ea78fa51e.png
[image-20200611150701238]: /images/20221123/d58820299c984ecda5fa490d56b397f2.png
[image-20200611150826737]: /images/20221123/c8d16cdb611d427ba72961c7c933ec43.png
[image-20200611151604944]: /images/20221123/7c28430c618e4cb0807852ad087b40b1.png
[image-20200611152912242]: /images/20221123/683d8e4630314c3eb9983b2d475e172a.png
[image-20200611153454410]: /images/20221123/0178e729a25844ff8a21b48d556cf0fe.png
[image-20200611153605288]: /images/20221123/ec4ed246364f46b09f9aad86c758a16d.png
[image-20200611154114134]: /images/20221123/b45cda8837c640af9d9be4cc4e40ad97.png
[image-20200611161028488]: /images/20221123/028e8c721e8841b4b09eab5a523d4b5a.png
[image-20200611161624583]: /images/20221123/decee82132924451bdc291bad2377bff.png
[image-20200611161839286]: /images/20221123/33f2c8a640374493996f9f76112339b9.png
[image-20200611164803787]: /images/20221123/80d53835005646b2b0758bef9b84f349.png
[image-20200611165810832]: /images/20221123/b09706106c8542aba6104fb068967268.png
[image-20200611165612747]: /images/20221123/107f1eb3a9c94383a747a7763da8ff8e.png
[image-20200611192707341]: /images/20221123/67dad469497d4c0aa67bc3aa83ae40ad.png
[image-20200611192206287]: /images/20221123/4721b30398ee4931841d3bdc63d51e65.png
[image-20200611212429605]: /images/20221123/c83b9645e986464e8b8a4648d1066364.png
[image-20200611212549366]: /images/20221123/5388b45025a64e61b4061e13e73ded69.png
[image-20200611212704950]: /images/20221123/cc3f83a83d7c44bbb4b79bb42020db96.png
[image-20200619104904312]: /images/20221123/45d68dc7a7ac4b19a1d757fd2aed92a3.png
[image-20200619105637979]: /images/20221123/ce9aca3cb5fe4388bb4faab854f8ef67.png
[image-20200619105642629]: /images/20221123/b598000899ab4a46b387c0fea7c03b60.png
[image-20200619105807912]: /images/20221123/c801f5a3a9874e65bd05bb09ffe5440a.png
[image-20200919184738292]: /images/20221123/e49294e59ab84d83a675a8c7ef4406b2.png
[image-20200611213658473]: /images/20221123/d1e583e5746d4181a21e2068379e4cee.png
[image-20200611213821803]: /images/20221123/ba354eefb9034c97bdbe16af294b8060.png
[image-20200611220431380]: /images/20221123/884ceb2cbf5f49bc8869cc783d626232.png
[image-20200611220646143]: /images/20221123/247343bd845648969fe9929538bfb3bc.png
[image-20200611220729015]: /images/20221123/3c08e7ac4f364f6bb6decdbe2190b049.png
[image-20200611221454231]: /images/20221123/cf1c0a05ccc4405e8bae4ddf264e9256.png
[image-20200611221549401]: /images/20221123/aa5a868c605741b9abbdb7c1832196cc.png
[image-20200611221703001]: /images/20221123/4d82236f0e6b412d84e799030e6c844e.png
[image-20200611221926174]: /images/20221123/af0d2f8675234161b0161473dab7be73.png
[image-20200611222407258]: /images/20221123/f04379fd2dec48f988fde5ddf946407b.png
[image-20200611222330699]: /images/20221123/6b6e95196a394cc3838a337032ef1ad1.png
[image-20200919184902637]: /images/20221123/99cefaa3e9024e56ab84aa4bb710559f.png
[image-20200612101421105]: /images/20221123/7e6c35caac574751b3b0363aaa9eeffa.png
[image-20200612101744867]: /images/20221123/a6201ab166a643ea8618cab70e3e515c.png
[image-20200612102330407]: /images/20221123/175a0bcab9774f2a96b37589583e25f1.png
[image-20200612102437433]: /images/20221123/dcd1465821a9459ab0ede890c8a035d6.png
[image-20200612103500808]: /images/20221123/d24bbef0bd2241e2af87db89e9418a29.png
[image-20200612103903537]: /images/20221123/d164f39a0bb64ea4b29f8c584b3cf46f.png
[image-20200612104317328]: /images/20221123/2ac17ab8a82e4b26a8b8343f14741d93.png
[image-20200612104501829]: /images/20221123/0a3ad418c2bd4612bbc3c39fe74cf9f0.png
[image-20200612150519969]: /images/20221123/5a933dd30f804d9f917f210055117899.png
[image-20200612150649060]: /images/20221123/c736725f71ba4670af2ab1ecc4561efe.png
[image-20200612151018040]: /images/20221123/a67c1a604548452b9efbd039313b3bc0.png
[image-20200612150158032]: /images/20221123/449750aace1c49fa9f9bcb85a5cb1a29.png
[image-20200612151419394]: /images/20221123/6e8d283373b1488ea1da6e202e42c2b6.png