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引入需要的依赖,创建必要的目录
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>表白墙</title> </head> <body> <form action="confession" method="post"> <div class="parent"> <div id="wall">表白墙</div> <div id="remind">输入后点击提交,会将信息显示在表格中</div> <div class="one"><span class="two">谁:</span><input type="text" class="text" name="from"></div> <div class="one"><span class="two">对谁:</span><input type="text" class="text" name="to"></div> <div class="one"><span class="two">说什么:</span><input type="text" class="text" name="message"></div> <div class="one"><input type="submit" value="提 交" class="press"></div> <div class="elem" th:each="message : ${messages}"> <span th:text="${message.from}">wz</span>对<span th:text="${message.to}">zw</span>说: <span th:text="${message.message}">wzz</span> </div> </div> </form> <style> /* 去除浏览器默认样式 */ * { margin: 0; padding: 0; } /* 设置总宽度 */ .parent { width: 400px; margin: 0 auto; } /* 设置表白墙样式 */ #wall { font-size: 30px; font-weight: 700; text-align: center; margin: 5px; } /* 设置提示信息样式 */ #remind{ font-size:13px; text-align: center; color:gray; margin: 5px; } /* 设置弹性布局 */ .one { display: flex; justify-content: center; align-items: center; height: 40px; } /* 设置文字内容 */ .two { width: 100px; line-height: 40px; } /* 设置输入框 */ .one .text{ width: 200px; height: 20px; padding-left: 3px; } /* 提交按钮的设置 */ .one .press{ width: 304px; height: 40px; color:white; background-color: orange; border-radius: 5px; border: none; } /* 设置鼠标点击的时候改变颜色 */ .one .press:active{ background-color: red; } /* 提交之后内容的设置 */ .elem { text-align: center; margin: 15px; } </style> </body> </html>
ConnectionDB 类
import com.mysql.cj.jdbc.MysqlDataSource; import javax.sql.DataSource; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class ConnectionDB { private static final String URL = "jdbc:mysql://127.0.0.1:3306/confessionWall2?characterEncoding=utf-8&useSSL=true&serverTimezone=UTC"; private static final String USERNAME = "root"; private static final String PASSWORD = "0000"; private static volatile DataSource dataSource = null; public static DataSource getDataSource() { if(dataSource == null){ synchronized (ConnectionDB.class){ if(dataSource == null) { dataSource = new MysqlDataSource(); ((MysqlDataSource) dataSource).setURL(URL); ((MysqlDataSource) dataSource).setUser(USERNAME); ((MysqlDataSource) dataSource).setPassword(PASSWORD); } } } return dataSource; } public static Connection getConnection() throws SQLException { return getDataSource().getConnection(); } public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet){ if(resultSet != null){ try { resultSet.close(); } catch (SQLException e) { e.printStackTrace(); } } if(statement != null){ try { statement.close(); } catch (SQLException e) { e.printStackTrace(); } } if(connection != null){ try { connection.close(); } catch (SQLException e) { e.printStackTrace(); } } } }
ThymeleafConfig
类
注意加上注解
import org.thymeleaf.TemplateEngine; import org.thymeleaf.templateresolver.ServletContextTemplateResolver; import javax.servlet.ServletContext; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import javax.servlet.annotation.WebListener; @WebListener public class ThymeleafConfig implements ServletContextListener { @Override public void contextInitialized(ServletContextEvent servletContextEvent) { System.out.println("ServletContext 初始化完毕!"); ServletContext context = servletContextEvent.getServletContext(); TemplateEngine engine = new TemplateEngine(); ServletContextTemplateResolver resolver = new ServletContextTemplateResolver(context); resolver.setPrefix("/WEB-INF/template/"); resolver.setSuffix(".html"); resolver.setCharacterEncoding("utf-8"); engine.setTemplateResolver(resolver); context.setAttribute("engine",engine); } @Override public void contextDestroyed(ServletContextEvent servletContextEvent) { } }
首先创建一个 Confession
类
class Confession{ public String from; public String to; public String message; }
① 重写 doGet 方法
@Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); List<Confession> list = load(); TemplateEngine engine = (TemplateEngine) getServletContext().getAttribute("engine"); WebContext webContext = new WebContext(req,resp,getServletContext()); webContext.setVariable("messages",list); engine.process("confessionwall",webContext, resp.getWriter()); }
② 重写 doPost 方法
resp.setContentType("text/html;charset=utf-8"); Confession confession = new Confession(); confession.from = req.getParameter("from"); confession.to = req.getParameter("to"); confession.message = req.getParameter("message"); save(confession); resp.sendRedirect("confession");
③ 实现 load 方法
private List<Confession> load() { List<Confession> list = new ArrayList<>(); Connection connection = null; PreparedStatement statement = null; ResultSet resultSet = null; try { connection = ConnectionDB.getConnection(); String sql = "select * from confession"; statement = connection.prepareStatement(sql); resultSet = statement.executeQuery(); while(resultSet.next()){ Confession confession = new Confession(); confession.from =resultSet.getString("from"); confession.to = resultSet.getString("to"); confession.message = resultSet.getString("message"); list.add(confession); } } catch (SQLException throwables) { throwables.printStackTrace(); } finally { ConnectionDB.close(connection,statement,resultSet); } return list; }
④ 实现 save 方法
private void save(Confession confession) { Connection connection = null; PreparedStatement statement = null; try{ connection = ConnectionDB.getConnection(); String sql = "insert into confession values (?,?,?)"; statement = connection.prepareStatement(sql); statement.setString(1,confession.from); statement.setString(2, confession.to); statement.setString(3,confession.message); int ret = statement.executeUpdate(); if(ret == 1){ System.out.println("插入成功"); }else{ System.out.println("插入失败"); } } catch (SQLException throwables) { throwables.printStackTrace(); } finally { ConnectionDB.close(connection,statement,null); } }
注意模板引擎
注意 乱码的情况,要添加utf-8
用数据库的方法存数据,要先创建好数据库
create database confessionWall2; use confessionWall2; create table confession( `from` varchar(1024), `to` varchar(1024), `message` varchar(1024) );
还有一些必要的注解也要加上.
浏览器输入对应的URL
在数据库为空的时候界面如下
在输入几个数据之后 如下
此时的数据库中表的内容
重新部署再进入URL发现数据还是存在.
引入必要的依赖,已经必要的目录
image.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>相册</title> <link rel="stylesheet" href="./style.css"> </head> <body> <div class="nav"> <form action="upload" method="POST" enctype="multipart/form-data" > <input type="file" name="myImage"> <input type="submit" value="上传图片"> </form> </div> <div class="parent"> <!-- 第一组图片 --> <figure class="sample" th:each="image : ${images}"> <img th:src="${image.url}" alt="sample1" /> <figcaption> <div> <h3 th:text="${image.name}">Deconovo</h3> </div> </figcaption> <a th:href="${image.url}"></a> </figure> </div> </body> </html>
style.css
/* 引入文字样式库 */ @import url(https://fonts.googleapis.com/css?family=Raleway:400,700); *{ margin: 0 auto; padding: 0 auto; box-sizing: border-box; } html,body{ width: 100%; height: calc(100% - 50px); background-color: #212121; } .parent{ display: flex; justify-content: center; align-items: center; flex-flow: wrap; margin: 0; height: 100%; } .nav{ background-color: rgba(255,255,255,0.3); height: 50px; width: 100%; display: flex; justify-content: left; align-items: center; } /* sample 部分的整体样式 */ .sample { font-family: 'Raleway', Arial, sans-serif; position: relative; overflow: hidden; margin: 10px; min-width: 230px; max-width: 315px; width: 100%; color: #ffffff; text-align: center; font-size: 16px; background-color: #000000; } .sample *, .sample *:before, .sample *:after { -webkit-box-sizing: border-box; box-sizing: border-box; /* 当过了 0.55s 过渡效果 */ -webkit-transition: all 0.55s ease; transition: all 0.55s ease; } /* 图片部分的样式 */ .sample img { max-width: 100%; backface-visibility: hidden; vertical-align: top; } /* figcaption 用作文档中插图的图像,带有一个标题 */ .sample figcaption { position: absolute; bottom: 25px; right: 25px; padding: 5px 10px 10px; } /* 绘制线条 */ .sample figcaption:before, .sample figcaption:after { height: 2px; width: 400px; position: absolute; content: ''; background-color: #ffffff; } /* 上面一条线 */ .sample figcaption:before { top: 0; left: 0; -webkit-transform: translateX(100%); transform: translateX(100%); } /* 下面一条线 */ .sample figcaption:after { bottom: 0; right: 0; -webkit-transform: translateX(-100%); transform: translateX(-100%); } /* 绘制线条 */ .sample figcaption div:before, .sample figcaption div:after { width: 2px; height: 300px; position: absolute; content: ''; background-color: #ffffff; } /* 左面一条线 */ .sample figcaption div:before { top: 0; left: 0; -webkit-transform: translateY(100%); transform: translateY(100%); } /* 右面一条线 */ .sample figcaption div:after { bottom: 0; right: 0; -webkit-transform: translateY(-100%); transform: translateY(-100%); } /* 文字部分 */ .sample h3, .sample h5 { margin: 0; text-transform: uppercase; } .sample h3 { font-weight: 400; } .sample h5 { display: block; font-weight: 700; background-color: #ffffff; padding: 5px 10px; color: #000000; } .sample a { position: absolute; top: 0; bottom: 0; left: 0; right: 0; } /* 当鼠标放到图片时的效果, .hover 仅演示需要,可自行取消 */ .sample:hover img, .sample.hover img { zoom: 1; filter: alpha(opacity=50); -webkit-opacity: 0.5; opacity: 0.5; } .sample:hover figcaption:before, .sample.hover figcaption:before, .sample:hover figcaption:after, .sample.hover figcaption:after, .sample:hover figcaption div:before, .sample.hover figcaption div:before, .sample:hover figcaption div:after, .sample.hover figcaption div:after { -webkit-transform: translate(0, 0); transform: translate(0, 0); } .sample:hover figcaption:before, .sample.hover figcaption:before, .sample:hover figcaption:after, .sample.hover figcaption:after { /* 过渡延时 0.15s */ -webkit-transition-delay: 0.15s; transition-delay: 0.15s; } /* 背景仅演示作用 */
在webapp下创建一个文件夹 image,里面存放图片.
通过 getServletContext().getRealPath("/image")
来获取绝对路径
这里的代码不变
import org.thymeleaf.TemplateEngine; import org.thymeleaf.templateresolver.ServletContextTemplateResolver; import javax.servlet.ServletContext; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import javax.servlet.annotation.WebListener; @WebListener public class ThymeleafConfig implements ServletContextListener { @Override public void contextInitialized(ServletContextEvent servletContextEvent) { System.out.println("ServletContext 初始化完毕"); ServletContext context = servletContextEvent.getServletContext(); TemplateEngine engine = new TemplateEngine(); ServletContextTemplateResolver resolver = new ServletContextTemplateResolver(context); resolver.setPrefix("/WEB-INF/template/"); resolver.setSuffix(".html"); resolver.setCharacterEncoding("utf-8"); engine.setTemplateResolver(resolver); context.setAttribute("engine",engine); } @Override public void contextDestroyed(ServletContextEvent servletContextEvent) { } }
创建一个 Image 类
class Image { public String name; public String url; }
创建一个类,重写 doGet 方法
@WebServlet("/Image") public class OnlineImageServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); // 1. 扫描指定路径 /webapp/image 路径 List<Image> images = loadImage(); // 2. 构造到模板页面 TemplateEngine engine = (TemplateEngine) getServletContext().getAttribute("engine"); WebContext webContext = new WebContext(req,resp,getServletContext()); webContext.setVariable("images",images); String html = engine.process("image",webContext); resp.getWriter().write(html); } }
实现 loadImage 方法
注意使用 getRealPath 方法
以及注意使用 file.listFiles()方法
private List<Image> loadImage() { List<Image> images = new ArrayList<>(); // 首先得到 /webapp/image 的绝对路径 ServletContext context = this.getServletContext(); // 这里是将 webapp下的目录转换成一个绝对路径 String path = context.getRealPath("/image"); // 根据路径 看里面有哪些图片. File file = new File(path); File[] files = file.listFiles(); for(File f:files){ Image image = new Image(); image.name = f.getName(); image.url = "image/"+f.getName(); images.add(image); } return images; }
① 创建一个类,重写 doPost 方法
注意一定要加上注解@MultipartConfig
import javax.servlet.ServletException; import javax.servlet.annotation.MultipartConfig; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.Part; import java.io.IOException; // 这个注解在上传文件的功能中是必要的 @MultipartConfig @WebServlet("/upload") public class UploadServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String path = getServletContext().getRealPath("/image"); Part part = req.getPart("myImage"); part.write(path + "/" + part.getSubmittedFileName()); resp.sendRedirect("Image"); } }
主要是得到文件夹,找到路径的步骤复杂点.重点掌握这几种方法的使用
前后端约定好的名称要对应.
传文件需要加上注解,否则会报500的错误.@MultipartConfig
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