Javaweb开发一般步骤

清疚 2021-07-24 19:48 407阅读 0赞

# 一 概念 #

以超市订单管理系统为例进行说明。

SMBMS：超市订单管理系统。

# 二 功能描述 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

# 三 数据库 #

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# 四 准备工作 #

考虑是否使用Maven？如果使用，需要添加依赖，如果不使用Maven，需要考虑引入Jar包。

这里使用Maven进行搭建。

# 五 搭建步骤 #

1 搭建一个Maven web项目

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2][]

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web.xml

2 配置Tomcat

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3 测试项目是否可以跑起来

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4 导入项目中的jar包

<?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>org.example</groupId>
      <artifactId>smbms</artifactId>
      <version>1.0-SNAPSHOT</version>
      <packaging>war</packaging>
      <dependencies>
        <dependency>
          <groupId>javax.servlet</groupId>
          <artifactId>servlet-api</artifactId>
          <version>2.5</version>
        </dependency>
        <dependency>
          <groupId>javax.servlet.jsp</groupId>
          <artifactId>javax.servlet.jsp-api</artifactId>
          <version>2.3.3</version>
        </dependency>
        <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.46</version>
        </dependency>
      </dependencies>
    </project>

5 创建项目包结构

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 7][]

6 编写实体类

ORM映射：表-类映射

7 编写基础公共类

7.1 数据库配置文件

db.properties

driver=com.mysql.jdbc.Driver
    url=jdbc:mysql://localhost:3306/smbms?useUnicode=true&characterEncoding=utf8
    username=root
    password=123456

7.2 编写数据库功能类

package com.cakin.dao;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.sql.*;
    import java.util.Properties;
    
    /**
     * @ClassName: BaseDao
     * @Description: 操作数据库的公共类
     * @Date: 2020/6/20
     * @Author: cakin
     */
    public class BaseDao {
        private static String driver;
        private static String url;
        private static String username;
        private static String password;
    
        /**
         * 静态代码块，类加载的时候就初始化
         */
        static {
            Properties properties = new Properties();
            // 通过类加载器读取对应的资源
            InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
            try {
                properties.load(is);
            } catch (IOException e) {
                e.printStackTrace();
            }
            driver = properties.getProperty("driver");
            url = properties.getProperty("url");
            username = properties.getProperty("username");
            password = properties.getProperty("password");
        }
    
        /**
         * 功能描述：获取数据库连接
         *
         * @return Connection 数据库连接
         * @author cakin
         * @date 2020/6/20
         */
        public static Connection getConnection() {
            Connection connection = null;
            try {
                Class.forName(driver);
                connection = DriverManager.getConnection(url, username, password);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return connection;
        }
    
        /**
         * 功能描述：查询公共方法
         *
         * @param connection        数据库连接
         * @param sql               查询语句
         * @param object            对象数组
         * @param resultSet         结果集
         * @param preparedStatement 预编译语句对象
         * @return ResultSet 结果集
         * @author cakin
         * @date 2020/6/20
         */
        public static ResultSet execute(Connection connection, String sql, Object[] object, ResultSet resultSet, PreparedStatement preparedStatement) throws SQLException {
            // 预编译的SQL，在后面直接执行就可以了
            PreparedStatement preparedStatement1 = connection.prepareStatement(sql);
            for (int i = 0; i < object.length; i++) {
                // setObject,占位符从1开始，但我们的数组从0开始
                preparedStatement.setObject(i + 1, object[i]);
            }
            resultSet = preparedStatement.executeQuery();
            return resultSet;
        }
    
        /**
         * 功能描述：增删改的公共方法
         *
         * @param connection        数据库连接
         * @param sql               查询语句
         * @param object            对象数组
         * @param preparedStatement 预编译语句对象
         * @return ResultSet 结果集
         * @author cakin
         * @date 2020/6/20
         */
        public static int execute(Connection connection, String sql, Object[] object, PreparedStatement preparedStatement) throws SQLException {
            // 预编译的SQL，在后面直接执行就可以了
            PreparedStatement preparedStatement1 = connection.prepareStatement(sql);
            for (int i = 0; i < object.length; i++) {
                // setObject,占位符从1开始，但我们的数组从0开始
                preparedStatement.setObject(i + 1, object[i]);
            }
            int updateCount = preparedStatement.executeUpdate();
            return updateCount;
        }
    
        /**
         * 功能描述：关闭资源
         *
         * @param connection        数据库连接
         * @param resultSet         结果集
         * @param preparedStatement 预编译语句对象
         * @return boolean boolean类型
         * @author cakin
         * @date 2020/6/20
         */
        public static boolean closeResource(Connection connection, ResultSet resultSet, PreparedStatement preparedStatement) {
            boolean flag = true;
            if (connection != null) {
                try {
                    connection.close();
                    connection = null;
                } catch (SQLException throwables) {
                    flag = false;
                    throwables.printStackTrace();
                }
            }
    
            if (resultSet != null) {
                try {
                    resultSet.close();
                    resultSet = null;
                } catch (SQLException throwables) {
                    flag = false;
                    throwables.printStackTrace();
                }
            }
    
            if (preparedStatement != null) {
                try {
                    preparedStatement.close();
                    preparedStatement = null;
                } catch (SQLException throwables) {
                    flag = false;
                    throwables.printStackTrace();
                }
            }
            return flag;
        }
    }

7.3 编写过滤器

package com.cakin.filter;
    
    import javax.servlet.*;
    import java.io.IOException;
    
    /**
     * @ClassName: CharacterEncodingFileter
     * @Description: 字符编码过滤器
     * @Date: 2020/6/20
     * @Author: cakin
     */
    public class CharacterEncodingFileter implements Filter {
        public void init(FilterConfig filterConfig) throws ServletException {
    
        }
        /**
         * 功能描述：解决中文乱码问题
         *
         * @author cakin
         * @date 2020/6/20
         * @param request 请求
         * @param response 响应
         * @param chain 过滤器链
         */
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
            request.setCharacterEncoding("utf-8");
            response.setCharacterEncoding("utf-8");
            chain.doFilter(request,response);
        }
    
        public void destroy() {
    
        }
    }

7.4 编写web.xml

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
             http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
             version="4.0"
              metadata-complete="true">
        
        <filter>
            <filter-name>CharacterEncodingFileter</filter-name>
            <filter-class>com.cakin.filter.CharacterEncodingFileter</filter-class>
        </filter>
        <filter-mapping>
            <filter-name>CharacterEncodingFileter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    </web-app>

8 导入静态资源

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 8][]

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