标签：pack   dea   释放   字符   字符编码   网站   lan   import   character   

一、 项目搭建准备工作

1. 创建maven web项目，配置Tomcat

• 具体见博文

2. 测试项目是否跑得起来

3. 导入项目中会遇到的jar包（maven依赖）

• servlet，jsp，mysql，jstl依赖

  去这个网站找：https://mvnrepository.com/

  <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>5.1.47</version>
      </dependency>
      <!-- JSTL表达式的依赖 -->
      <dependency>
          <groupId>javax.servlet.jsp.jstl</groupId>
          <artifactId>jstl</artifactId>
          <version>1.2</version>
      </dependency>
      <!-- standard标签库 -->
      <dependency>
          <groupId>org.apache.taglibs</groupId>
          <artifactId>taglibs-standard-impl</artifactId>
          <version>1.2.5</version>
      </dependency>
  </dependencies>
  

4. 创建项目包结构

• 项目结构（忽略我的jsp和html文件）

  

5. 连接数据库

6. 编写实体类

7. 编写基础公共类

1. 数据库配置文件

   （我的编码全是gbk）

   driver = com.mysql.jdbc.Driver
   url= jdbc:mysql://localhost:3306/TutorSelectSys?useUnicode=true&characterEncoding=gbk
   user = root
   password = root
   

2. 编写数据库的公共类BaseDao

   package dao;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.sql.*;
   import java.util.Properties;
   
   /**
    * 操作数据库的公共类
    */
   public class BaseDao {
       private static String driver;
       private static String url;
       private static String user;
       private static String password;
   
       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");
           user = properties.getProperty("user");
           password = properties.getProperty("password");
       }
   
       //获取数据库的链接
       public static Connection getConnection() {
           Connection conn = null;
           try {
               Class.forName(driver);
               conn = DriverManager.getConnection(url, user, password);
           } catch (Exception e) {
               e.printStackTrace();
           }
           return conn;
       }
   
       //查询公共方法
       public static ResultSet executeQuery(Connection conn, String sql, Object[] params, PreparedStatement ps, ResultSet rs) throws SQLException {
           ps = conn.prepareStatement(sql);
           for (int i = 0; i < params.length; i++) {
               //注意：setObject占位符从1开始，数组从0开始
               ps.setObject(i + 1, params[i]);
           }
   
           rs = ps.executeQuery();
           return rs;
       }
   
       //增删改公共方法
       public static int executeUpdate(Connection conn, String sql, Object[] params, PreparedStatement ps) throws SQLException {
           ps = conn.prepareStatement(sql);
           for (int i = 0; i < params.length; i++) {
               //注意：setObject占位符从1开始，数组从0开始
               ps.setObject(i + 1, params[i]);
           }
   
           int updateRows = ps.executeUpdate();
           return updateRows;
       }
   
       //释放资源
       public static boolean closeResource(Connection conn, PreparedStatement ps, ResultSet rs) {
           boolean flag = true;
   
           if (rs != null) {
               try {
                   rs.close();
                   //GC回收
                   rs = null;
               } catch (SQLException e) {
                   e.printStackTrace();
                   flag = false;
               }
           }
   
           if (ps != null) {
               try {
                   ps.close();
                   //GC回收
                   ps = null;
               } catch (SQLException e) {
                   e.printStackTrace();
                   flag = false;
               }
           }
   
           if (conn != null) {
               try {
                   conn.close();
                   //GC回收
                   conn = null;
               } catch (SQLException e) {
                   e.printStackTrace();
                   flag = false;
               }
           }
   
           return flag;
       }
   
   
   }
   

   
   

3. 编写字符编码过滤器

   package filter;
   
   import javax.servlet.*;
   import javax.servlet.annotation.WebFilter;
   import java.io.IOException;
   
   /**
    * 字符编码过滤器
    */
   @WebFilter("/*")
   public class CharacterEncodingFilter implements Filter {
   
       @Override
       public void init(FilterConfig filterConfig) throws ServletException {
   
       }
   
       @Override
       public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
           servletRequest.setCharacterEncoding("gbk");
           servletResponse.setCharacterEncoding("gbk");
   
           filterChain.doFilter(servletRequest,servletResponse);
       }
   
       @Override
       public void destroy() {
   
       }
   }
   

8. 导入静态资源

js，css等

9. 编写字符编码过滤器（哪步写都行）

• CharacterEncodingFilter

  @WebFilter("/*")
  public class CharacterEncodingFilter implements Filter {
  
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
  
      }
  
      @Override
      public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
          servletRequest.setCharacterEncoding("gbk");
          servletResponse.setCharacterEncoding("gbk");
  
          filterChain.doFilter(servletRequest,servletResponse);
      }
  
      @Override
      public void destroy() {
  
      }
  }
  

完成一个IDEA web项目（一）项目搭建准备工作

标签：pack   dea   释放   字符   字符编码   网站   lan   import   character   

原文地址：https://www.cnblogs.com/musecho/p/13021554.html