概述
为了增强邮件内容展示的样式，可以将普通的文本邮件转换为HTML内容格式。 在Java中，可以通过页面模板技术来实现。具体来说，可以使用Thymeleaf模板。
具体实现
首先，在项目中引入Thymeleaf依赖：
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
<version>3.0.15.RELEASE</version>
</dependency>其次，编写页面模板内容：
代码语言：javascript复制<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>TOP100车系车友圈精华帖双周增量监控</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style type="text/css">
.znwh_tb {
border: 1px solid rgba(87, 84, 84, 0.99);
border-collapse:collapse;
}
.znwh_tb th,
.znwh_tb td {
border: 1px solid #545454;
padding: 3px 5px;
}
.znwh_tb th {
background-color:#DCDCDC;
}
</style>
</head>
<body style="margin: 0; padding: 0;">
<h3>精华帖统计</h3>
<p>时间：<span th:text="${startDate}"></span>-<span th:text="${endDate}"></span>，新增帖子数：<span th:text="${bbsIncrement}"></span></p>
<h3>按阅读数倒序TOP<span th:text="${topSize}"></span>精华帖列表</h3>
<table class="znwh_tb">
<tr>
<th>序号</th><th>发帖时间</th><th>加精日期</th><th>阅读数</th><th>评论数</th><th>点赞数</th><th>分享数</th><th>车系</th><th>标题</th>
</tr>
<tr th:each="bbs,bbsStat:${bbsList}">
<td th:text="${bbsStat.index 1}"></td>
<td th:text="${#dates.format(bbs.publishTimeDate, 'yyyy-MM-dd HH:mm:ss')}"></td>
<td th:text="${#dates.format(bbs.createdStimeDate, 'yyyy-MM-dd HH:mm:ss')}"></td>
<td th:text="${bbs.viewCount}"></td>
<td th:text="${bbs.commentCount}"></td>
<td th:text="${bbs.likeCount}"></td>
<td th:text="${bbs.shareCount}"></td>
<td th:text="${bbs.seriesName}"></td>
<td><a th:href="@{${bbs.originUrl}}" rel="noopener noreferrer"><span th:text="${bbs.title}"></span></a></td>
</tr>
</table>
<p><b>注：</b>完整数据详见附件文档。</p>
</body>
</html>最后，加载页面模板渲染最终结果。
代码语言：javascript复制private static void buildTop100SeriesBbsMail(List<CyqBbs> bbsList) throws IOException {
//构造模板引擎
ClassLoaderTemplateResolver resolver = new ClassLoaderTemplateResolver();
resolver.setPrefix("templates/");//模板所在目录，相对于当前classloader的classpath。
resolver.setSuffix(".html");//模板文件后缀
TemplateEngine templateEngine = new TemplateEngine();
templateEngine.setTemplateResolver(resolver);
//构造上下文(Model)
Context context = new Context();
context.setVariable("startDate", "10.21");
context.setVariable("endDate", "11.10");
context.setVariable("bbsIncrement", "100");
context.setVariable("topSize", "50");
context.setVariable("bbsList", bbsList);
//渲染模板
String fileName = "dcd_result.html";
FileWriter write = new FileWriter(fileName);
templateEngine.process("dcd_top100series_bbs_monitor_mail", context, write);
write.close();
}
public static void main(String[] args) throws IOException {
CyqBbs bbs = CyqBbs.builder()
.id(10)
.publishTimeDate(Calendar.getInstance().getTime())
.createdStime(LocalDateTime.now())
.behotTime(System.currentTimeMillis())
.seriesName("艾薇塔11")
.viewCount(100)
.commentCount(1000)
.likeCount(10)
.shareCount(2)
.originUrl("http://www.baidu.com")
.title("测试数据")
.build();
ZoneId zoneId = ZoneId.systemDefault();
ZonedDateTime zdt = bbs.getCreatedStime().atZone(zoneId);
Date createdTimeDate = Date.from(zdt.toInstant());
bbs.setCreatedStimeDate(createdTimeDate);
List<CyqBbs> bbsList = Collections.singletonList(bbs);
buildTop100SeriesBbsMail(bbsList);
}最终输出的结果如下：
代码语言：javascript复制<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>TOP100车系车友圈精华帖双周增量监控</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style type="text/css">
.znwh_tb {
border: 1px solid rgba(87, 84, 84, 0.99);
border-collapse:collapse;
}
.znwh_tb th,
.znwh_tb td {
border: 1px solid #545454;
padding: 3px 5px;
}
.znwh_tb th {
background-color:#DCDCDC;
}
</style>
</head>
<body style="margin: 0; padding: 0;">
<h3>精华帖统计</h3>
<p>时间：<span>10.21</span>-<span>11.10</span>，新增帖子数：<span>100</span></p>
<h3>按阅读数倒序TOP<span>50</span>精华帖列表</h3>
<table class="znwh_tb">
<tr>
<th>序号</th><th>发帖时间</th><th>加精日期</th><th>阅读数</th><th>评论数</th><th>点赞数</th><th>分享数</th><th>车系</th><th>标题</th>
</tr>
<tr>
<td>1</td>
<td>2022-12-21 18:34:25</td>
<td>2022-12-21 18:34:26</td>
<td>100</td>
<td>1000</td>
<td>10</td>
<td>2</td>
<td>艾薇塔11</td>
<td><a href="http://www.baidu.com" rel="noopener noreferrer"><span>测试数据</span></a></td>
</tr>
</table>
<p><b>注：</b>完整数据详见附件文档。</p>
</body>
</html>这里要注意： 不同的邮件客户端对于css样式的兼容效果不同，所以最好对常见的邮件客户端展示结果做一下充分的测试。
相比起使用页面模板技术实现的HTML邮件，直接手动输出HTML内容的方式就显得非常笨拙，且不容易维护。 如下是手动输出HTML字符串的实现方式参考：
代码语言：javascript复制private static String buildTop100SeriesBbsHtmlStr(List<CyqBbs> bbsList) {
StringBuilder builder = new StringBuilder();
builder.append("<html>");
builder.append("<head>");
builder.append("<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />");
builder.append("<title>TOP100车系车友圈精华帖双周增量监控</title>");
builder.append("<meta name="viewport" content="width=device-width, initial-scale=1.0"/>");
builder.append("<style type="text/css">");
builder.append(".znwh_tb { border: 1px solid rgba(87, 84, 84, 0.99);border-collapse:collapse; }");
builder.append(".znwh_tb th,.znwh_tb td {border: 1px solid #545454; padding: 3px 5px; }");
builder.append(".znwh_tb th { background-color:#DCDCDC; }");
builder.append("</style>");
builder.append("</head>");
builder.append("<body style="margin: 0; padding: 0;">");
builder.append("<h3>精华帖统计</h3>");
builder.append("<p>时间：").append("10.21").append("-").append("11.10").append("，新增帖子数：").append(100).append("</p>");
builder.append("<h3>按阅读数倒序TOP").append(50).append("精华帖列表</h3>");
builder.append("<table class="znwh_tb">");
builder.append("<tr><th>序号</th><th>发帖时间</th><th>加精日期</th><th>阅读数</th><th>评论数</th><th>点赞数</th><th>分享数</th><th>车系</th><th>标题</th></tr>");
for (int i = 0; i < bbsList.size(); i ) {
CyqBbs bbs = bbsList.get(i);
builder.append("<tr>");
builder.append("<td>").append(i).append("</td>");
builder.append("<td>").append(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(bbs.getPublishTimeDate())).append("</td>");
builder.append("<td>").append(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(bbs.getBehotTime()))).append("</td>");
builder.append("<td>").append(bbs.getViewCount()).append("</td>");
builder.append("<td>").append(bbs.getCommentCount()).append("</td>");
builder.append("<td>").append(bbs.getLikeCount()).append("</td>");
builder.append("<td>").append(bbs.getShareCount()).append("</td>");
builder.append("<td>").append(bbs.getSeriesName()).append("</td>");
builder.append("<td>").append("<a href="").append(bbs.getOriginUrl()).append("" rel="noopener noreferrer">").append(bbs.getTitle()).append("</a>").append("</td>");
builder.append("</tr>");
}
builder.append("</table>");
builder.append("<p><b>注：</b>完整数据详见附件文档。</p>");
builder.append("</body>");
builder.append("</html>");
return builder.toString();
}它们使用到的共同实体类定义如下：
代码语言：javascript复制@Data
@Builder
static class CyqBbs {
private Integer id;
private String title;
private String content;
private String originUrl;
private String authorName;
private String cover;
private String keywords;
private String tags;
private String seriesId;
private String seriesName;
private Integer commentCount;
private Integer likeCount;
private Integer viewCount;
private Integer playCount;
private Integer shareCount;
private Integer duration;
private Long publishTime;
private Date publishTimeDate;
private Long behotTime;
private LocalDateTime createdStime;
private Date createdStimeDate;
private LocalDateTime modifiedStime;
}
