自定义MVC增删改查(终极篇)-阿里云开发者社区

1.框架配置

1.1将框架达成jar包，然后导入新工程，并且把框架的依赖jar包导入进去

将我们前面写的代码打成一个jar包然后导入我们的项目：

点击导出后我们搜索jar，点击JAR file(第一个选项)：

然后自己把jar包放在自己清楚的路径里：

之后我们把导出的jar包copy到WEB-INF安全目录下的lib文件夹中即可使用jar包中的方法。

1.2在这之后呢我们只需要导入其他的和依赖（助手类、baseDao······）

tag：

package com.Kissship.tag;
import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;
import com.Kissship.util.PageBean;
public class PageTag extends BodyTagSupport{
  private PageBean pageBean;// 包含了所有分页相关的元素
  public PageBean getPageBean() {
    return pageBean;
  }
  public void setPageBean(PageBean pageBean) {
    this.pageBean = pageBean;
  }
  @Override
  public int doStartTag() throws JspException {
//    没有标签体，要输出内容
    JspWriter out = pageContext.getOut();
    try {
      out.print(toHTML());
    } catch (IOException e) {
      e.printStackTrace();
    }
    return super.doStartTag();
  }
  private String toHTML() {
    StringBuffer sb = new StringBuffer();
//    隐藏的form表单---这个就是上一次请求下次重新发的奥义所在
//    上一次请求的URL
    sb.append("<form action='"+pageBean.getUrl()+"' id='pageBeanForm' method='post'>");
    sb.append(" <input type='hidden' name='page'>");
//    上一次请求的参数
    Map<String, String[]> paramMap = pageBean.getParamMap();
    if(paramMap != null && paramMap.size() > 0) {
      Set<Entry<String, String[]>> entrySet = paramMap.entrySet();
      for (Entry<String, String[]> entry : entrySet) {
//        参数名
        String key = entry.getKey();
//        参数值
        for (String value : entry.getValue()) {
//          上一次请求的参数，再一次组装成了新的Form表单
//          注意：page参数每次都会提交，我们需要避免
          if(!"page".equals(key)) {
            sb.append(" <input type='hidden' name='"+key+"' value='"+value+"' >");
          }
        }
      }
    }
    sb.append("</form>");
//    分页条
    sb.append("<ul class='pagination justify-content-center'>");
    sb.append(" <li class='page-item "+(pageBean.getPage() == 1 ? "disabled" : "")+"'><a class='page-link'");
    sb.append(" href='javascript:gotoPage(1)'>首页</a></li>");
    sb.append(" <li class='page-item "+(pageBean.getPage() == 1 ? "disabled" : "")+"'><a class='page-link'");
    sb.append(" href='javascript:gotoPage("+pageBean.previousPage()+")'>&lt;</a></li>");// less than 小于号
//    sb.append(" <li class='page-item'><a class='page-link' href='#'>1</a></li>");
//    sb.append(" <li class='page-item'><a class='page-link' href='#'>2</a></li>");
    sb.append(" <li class='page-item active'><a class='page-link' href='#'>"+pageBean.getPage()+"</a></li>");
    sb.append(" <li class='page-item "+(pageBean.getPage() == pageBean.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.nextPage()+")'>&gt;</a></li>");
    sb.append(" <li class='page-item "+(pageBean.getPage() == pageBean.maxPage() ? "disabled" : "")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.maxPage()+")'>尾页</a></li>");
    sb.append(" <li class='page-item go-input'><b>到第</b><input class='page-link'");
    sb.append(" type='text' id='skipPage' name='' /><b>页</b></li>");
    sb.append(" <li class='page-item go'><a class='page-link'");
    sb.append(" href='javascript:skipPage()'>确定</a></li>");
    sb.append(" <li class='page-item'><b>共"+pageBean.getTotal()+"条</b></li>");
    sb.append("</ul>");
//    分页执行的JS代码
    sb.append("<script type='text/javascript'>");
    sb.append(" function gotoPage(page) {");
    sb.append("   document.getElementById('pageBeanForm').page.value = page;");
    sb.append("   document.getElementById('pageBeanForm').submit();");
    sb.append(" }");
    sb.append(" function skipPage() {");
    sb.append("   var page = document.getElementById('skipPage').value;");
    sb.append("   if (!page || isNaN(page) || parseInt(page) < 1 || parseInt(page) > "+pageBean.maxPage()+") {");
    sb.append("     alert('请输入1~"+pageBean.maxPage()+"的数字');");
    sb.append("     return;");
    sb.append("   }");
    sb.append("   gotoPage(page);");
    sb.append(" }");
    sb.append("</script>");
    return sb.toString();
  }
}

BaseDao：

package com.Kissship.util;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
/**
 * BaseDao 所有Dao类的父亲
 * @author jj
 *
 * @param <T>
 */
public class BaseDao<T> {
  /*
   * 通用增删改方法
   * sql---->增删改SQL
   * t---->SQL中的表对应的实体类
   * attrs---->实体类对应的属性
   * 
   */
  public int executeUpdate(String sql, T t, String[] attrs) throws Exception {
    Connection conn = DBAccess.getConnection();
    PreparedStatement ps = conn.prepareStatement(sql);
    for (int i = 0; i < attrs.length; i++) {
      Field f = t.getClass().getDeclaredField(attrs[i]);
      f.setAccessible(true);
      ps.setObject(i+1, f.get(t));
    }
    return ps.executeUpdate();
  }
  /**
   * 通用分页查询
   * @param sql
   * @param clz
   * @return
   * @throws Exception
   */
  public List<T> executeQuery(String sql,Class<T> clz,PageBean pageBean) throws Exception{
    List<T> list = new ArrayList<T>();
    Connection con = DBAccess.getConnection();;
    PreparedStatement pst = null;
    ResultSet rs = null;
    /*
     * 是否需要分页？
     *  无需分页（项目中的下拉框，查询条件教员下拉框，无须分页）  
     *  必须分页（项目中列表类需求、订单列表、商品列表、学生列表...）
     */
    if(pageBean != null && pageBean.isPagination()) {
//      必须分页（列表需求）
      String countSQL = getCountSQL(sql);
      pst = con.prepareStatement(countSQL);
      rs = pst.executeQuery();
      if(rs.next()) {
        pageBean.setTotal(String.valueOf(rs.getObject(1)));
      }
//      挪动到下面，是因为最后才处理返回的结果集
//      -- sql=SELECT * FROM t_mvc_book WHERE bname like '%圣墟%'
//      -- pageSql=sql limit (page-1)*rows,rows   对应某一页的数据
//      -- countSql=select count(1) from (sql) t  符合条件的总记录数
      String pageSQL = getPageSQL(sql,pageBean);//符合条件的某一页数据
      pst = con.prepareStatement(pageSQL);
      rs = pst.executeQuery();
    }else {
//      不分页（select需求）
      pst = con.prepareStatement(sql);//符合条件的所有数据
      rs = pst.executeQuery();
    }
    while (rs.next()) {
      T t = clz.newInstance();
      Field[] fields = clz.getDeclaredFields();
      for (Field f : fields) {
        f.setAccessible(true);
        f.set(t, rs.getObject(f.getName()));
      }
      list.add(t);
    }
    return list;
  }
  /**
   * 将原生SQL转换成符合条件的总记录数countSQL
   * @param sql
   * @return
   */
  private String getCountSQL(String sql) {
//    -- countSql=select count(1) from (sql) t  符合条件的总记录数
    return "select count(1) from ("+sql+") t";
  }
  /**
   * 将原生SQL转换成pageSQL
   * @param sql
   * @param pageBean
   * @return
   */
  private String getPageSQL(String sql,PageBean pageBean) {
//    (this.page - 1) * this.rows
//    pageSql=sql limit (page-1)*rows,rows
    return sql + " limit "+ pageBean.getStartIndex() +","+pageBean.getRows();
  }
}

PageBean：

package com.Kissship.util;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
/**
 * 分页工具类
 *
 */
public class PageBean {
  private int page = 1;// 页码
  private int rows = 10;// 页大小
  private int total = 0;// 总记录数
  private boolean pagination = true;// 是否分页
  private String url; //保存上一次请求的URL
  private Map<String,String[]> paramMap = new HashMap<>();// 保存上一次请求的参数
  /**
   * 初始化pagebean的，保存上一次请求的重要参数
   * @param req
   */
  public void setRequest(HttpServletRequest req) {
//    1.1 需要保存上一次请求的URL
    this.setUrl(req.getRequestURL().toString());
//    1.2 需要保存上一次请求的参数  bname、price
    this.setParamMap(req.getParameterMap());
//    1.3 需要保存上一次请求的分页设置  pagination
    this.setPagination(req.getParameter("pagination"));
//    1.4 需要保存上一次请求的展示条目数
    this.setRows(req.getParameter("rows"));
//    1.5  初始化请求的页码 page
    this.setPage(req.getParameter("page"));
  }
  public void setPage(String page) {
    if(StringUtils.isNotBlank(page))
      this.setPage(Integer.valueOf(page));
  }
  public void setRows(String rows) {
    if(StringUtils.isNotBlank(rows))
      this.setRows(Integer.valueOf(rows));
  }
  public void setPagination(String pagination) {
//    只有在前台jsp填写了pagination=false，才代表不分页
    if(StringUtils.isNotBlank(pagination))
      this.setPagination(!"false".equals(pagination));
  }
  public String getUrl() {
    return url;
  }
  public void setUrl(String url) {
    this.url = url;
  }
  public Map<String, String[]> getParamMap() {
    return paramMap;
  }
  public void setParamMap(Map<String, String[]> paramMap) {
    this.paramMap = paramMap;
  }
  public PageBean() {
    super();
  }
  public int getPage() {
    return page;
  }
  public void setPage(int page) {
    this.page = page;
  }
  public int getRows() {
    return rows;
  }
  public void setRows(int rows) {
    this.rows = rows;
  }
  public int getTotal() {
    return total;
  }
  public void setTotal(int total) {
    this.total = total;
  }
  public void setTotal(String total) {
    this.total = Integer.parseInt(total);
  }
  public boolean isPagination() {
    return pagination;
  }
  public void setPagination(boolean pagination) {
    this.pagination = pagination;
  }
  /**
   * 获得起始记录的下标
   * 
   * @return
   */
  public int getStartIndex() {
    return (this.page - 1) * this.rows;
  }
  /**
   * 最大页
   * @return
   */
  public int maxPage() {
//    total % rows == 0 ? total / rows : total / rows +1
    return this.total % this.rows == 0 ? this.total / this.rows : this.total / this.rows + 1;
  }
  /**
   * 下一页
   * @return
   */
  public int nextPage() {
//    如果当前页小于最大页，那就下一页为当前页+1；如果不小于，说明当前页就是最大页，那就无需+1
    return this.page < this.maxPage() ? this.page + 1 : this.page;
  }
  /**
   * 上一页
   * @return
   */
  public int previousPage() {
    return this.page > 1 ? this.page - 1 : this.page;
  }
  @Override
  public String toString() {
    return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";
  }
}

DBAccess：

package com.Kissship.util;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/**
 * 提供了一组获得或关闭数据库对象的方法
 * 
 */
public class DBAccess {
  private static String driver;
  private static String url;
  private static String user;
  private static String password;
  static {// 静态块执行一次，加载 驱动一次
    try {
      InputStream is = DBAccess.class
          .getResourceAsStream("config.properties");
      Properties properties = new Properties();
      properties.load(is);
      driver = properties.getProperty("driver");
      url = properties.getProperty("url");
      user = properties.getProperty("user");
      password = properties.getProperty("pwd");
      Class.forName(driver);
    } catch (Exception e) {
      e.printStackTrace();
      throw new RuntimeException(e);
    }
  }
  /**
   * 获得数据连接对象
   * 
   * @return
   */
  public static Connection getConnection() {
    try {
      Connection conn = DriverManager.getConnection(url, user, password);
      return conn;
    } catch (SQLException e) {
      e.printStackTrace();
      throw new RuntimeException(e);
    }
  }
  public static void close(ResultSet rs) {
    if (null != rs) {
      try {
        rs.close();
      } catch (SQLException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  }
  public static void close(Statement stmt) {
    if (null != stmt) {
      try {
        stmt.close();
      } catch (SQLException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  }
  public static void close(Connection conn) {
    if (null != conn) {
      try {
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  }
  public static void close(Connection conn, Statement stmt, ResultSet rs) {
    close(rs);
    close(stmt);
    close(conn);
  }
  public static boolean isOracle() {
    return "oracle.jdbc.driver.OracleDriver".equals(driver);
  }
  public static boolean isSQLServer() {
    return "com.microsoft.sqlserver.jdbc.SQLServerDriver".equals(driver);
  }
  public static boolean isMysql() {
    return "com.mysql.cj.jdbc.Driver".equals(driver);
  }
  public static void main(String[] args) {
    Connection conn = DBAccess.getConnection();
    System.out.println(conn);
    DBAccess.close(conn);
    System.out.println("isOracle：" + isOracle());
    System.out.println("isSQLServer：" + isSQLServer());
    System.out.println("isMysql：" + isMysql());
    System.out.println("数据库连接(关闭)成功");
  }
}

过滤器：

package com.Kissship.util;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 中文乱码处理
 * 
 */
@WebFilter("*.action")
public class EncodingFiter implements Filter {
  private String encoding = "UTF-8";// 默认字符集
  public EncodingFiter() {
    super();
  }
  public void destroy() {
  }
  public void doFilter(ServletRequest request, ServletResponse response,
      FilterChain chain) throws IOException, ServletException {
    HttpServletRequest req = (HttpServletRequest) request;
    HttpServletResponse res = (HttpServletResponse) response;
    // 中文处理必须放到 chain.doFilter(request, response)方法前面
    res.setContentType("text/html;charset=" + this.encoding);
    if (req.getMethod().equalsIgnoreCase("post")) {
      req.setCharacterEncoding(this.encoding);
    } else {
      Map map = req.getParameterMap();// 保存所有参数名=参数值(数组)的Map集合
      Set set = map.keySet();// 取出所有参数名
      Iterator it = set.iterator();
      while (it.hasNext()) {
        String name = (String) it.next();
        String[] values = (String[]) map.get(name);// 取出参数值[注：参数值为一个数组]
        for (int i = 0; i < values.length; i++) {
          values[i] = new String(values[i].getBytes("ISO-8859-1"),
              this.encoding);
        }
      }
    }
    chain.doFilter(request, response);
  }
  public void init(FilterConfig filterConfig) throws ServletException {
    String s = filterConfig.getInitParameter("encoding");// 读取web.xml文件中配置的字符集
    if (null != s && !s.trim().equals("")) {
      this.encoding = s.trim();
    }
  }
}

StringUtils：

package com.Kissship.util;
public class StringUtils {
  // 私有的构造方法，保护此类不能在外部实例化
  private StringUtils() {
  }
  /**
   * 如果字符串等于null或去空格后等于""，则返回true，否则返回false
   * 
   * @param s
   * @return
   */
  public static boolean isBlank(String s) {
    boolean b = false;
    if (null == s || s.trim().equals("")) {
      b = true;
    }
    return b;
  }
  /**
   * 如果字符串不等于null或去空格后不等于""，则返回true，否则返回false
   * 
   * @param s
   * @return
   */
  public static boolean isNotBlank(String s) {
    return !isBlank(s);
  }
}

1.3框架的配置文件添加、以及web.xml的配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>Kissship_mvc_crud</display-name>
  <servlet>
    <servlet-name>mvc</servlet-name>
    <servlet-class>com.zking.framework.DispatchServlet</servlet-class>
    <init-param>
      <param-name>configurationLocation</param-name>
      <param-value>/mvc.xml</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>mvc</servlet-name>
    <url-pattern>*.action</url-pattern>
  </servlet-mapping>
</web-app>

2.通用增删改

通过最近的学习，发现我之前写增删改查的代码很繁琐而且有待改进。可以利用自定义MVC框架来做到简化冗余代码的同时实现与之相同的功能。这是我的学习代码(以书籍管理系统为例)，如下：

首先我们要新建一个Book实体类：

package com.Kissship.entity;
public class Book {
  private int bid;
  private String bname;
  private float price;
  public int getBid() {
    return bid;
  }
  public void setBid(int bid) {
    this.bid = bid;
  }
  public String getBname() {
    return bname;
  }
  public void setBname(String bname) {
    this.bname = bname;
  }
  public float getPrice() {
    return price;
  }
  public void setPrice(float price) {
    this.price = price;
  }
  public Book(int bid, String bname, float price) {
    super();
    this.bid = bid;
    this.bname = bname;
    this.price = price;
  }
  public Book() {
    super();
  }
  @Override
  public String toString() {
    return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
  }
}

在实体类完成后我们就可以编写Dao方法了，这里我注释的是繁琐的代码，没注释的则是优化后的代码，如下：

Dao方法：

package com.Kissship.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.List;
import com.Kissship.entity.Book;
import com.Kissship.util.BaseDao;
import com.Kissship.util.DBAccess;
import com.Kissship.util.PageBean;
import com.Kissship.util.StringUtils;
public class BookDao extends BaseDao<Book> {
  public List<Book> list(Book book, PageBean pageBean) throws Exception {
    String sql = "select * from t_mvc_book where 1=1";
    String bname = book.getBname();
    int bid = book.getBid();
    if (StringUtils.isNotBlank(bname)) {
      sql += "and bname like '%" + bname + "%'";
    }
    // bid == 0 意味着前台没有传递bid值
    if (bid != 0) {
      sql += "and bid = " + bid;
    }
    return super.executeQuery(sql, Book.class, pageBean);
  }
  /*
   * 1.重复的代码 Connection conn = DBAccess.getConnection(); PreparedStatement ps =
   * conn.prepareStatement(sql); 2.代码的逻辑是重复的------->就是将sql中占位符?赋值 ps.setObject(1,
   * book.getBid()); ps.setObject(2, book.getBname()); ps.setObject(3,
   * book.getPrice());
   */
  // 增加
  // public int add(Book book) throws Exception {
  // String sql = "insert into t_mvc_book values(?,?,?)";
  // Connection conn = DBAccess.getConnection();
  // PreparedStatement ps = conn.prepareStatement(sql);
  // ps.setObject(1, book.getBid());
  // ps.setObject(2, book.getBname());
  // ps.setObject(3, book.getPrice());
  // return ps.executeUpdate();
  // }
  // 删除
  // public int del(Book book) throws Exception {
  // String sql = "delete from t_mvc_book where bid = ?";
  // Connection conn = DBAccess.getConnection();
  // PreparedStatement ps = conn.prepareStatement(sql);
  // ps.setObject(1, book.getBid());
  // return ps.executeUpdate();
  // }
  // 修改
  // public int edit(Book book) throws SQLException {
  // String sql = "update t_mvc_book set bname = ?,price = ? where bid = ?";
  // Connection conn = DBAccess.getConnection();
  // PreparedStatement ps = conn.prepareStatement(sql);
  // ps.setObject(1, book.getBname());
  // ps.setObject(2, book.getPrice());
  // ps.setObject(3, book.getBid());
  // return ps.executeUpdate();
  // }
  // 新增
  public int add(Book book) throws Exception {
    String sql = "insert into t_mvc_book values(?,?,?)";
    return super.executeUpdate(sql, book, new String[] { "bid", "bname", "price" });
  }
  // 删除
  public int del(Book book) throws Exception {
    String sql = "delete from t_mvc_book where bid = ?";
    return super.executeUpdate(sql, book, new String[] { "bid" });
  }
  // 修改
  public int edit(Book book) throws Exception {
    String sql = "update t_mvc_book set bname = ?,price = ? where bid = ?";
    return super.executeUpdate(sql, book, new String[] { "bname", "price", "bid" });
  }
}

可以看到优化后的代码很明显变得简短很多。紧接着我们用JUnit来测试一下：

BookDAoTest：

package com.Kissship.dao;
import static org.junit.Assert.*;
import java.util.List;
import org.junit.Test;
import com.Kissship.entity.Book;
import com.Kissship.util.PageBean;
public class BookDaoTest {
  private BookDao bookDao = new BookDao();
  @Test
  public void testList() {
    Book book = new Book();
//    book.setBname("圣墟");
    PageBean pageBean = new PageBean();
//    pageBean.setPage(3);
    pageBean.setPagination(false);
    try {
      List<Book> lst = bookDao.list(book, pageBean);
      for (Book b : lst) {
        System.out.println(b);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
//  @Test
//  public void testAdd() {
//    Book book = new Book(150141318,"嘿嘿",99);
//    try {
//      bookDao.add(book);
//    } catch (Exception e) {
//      e.printStackTrace();
//    }
//  }
//  @Test
//  public void testDel() {
//    Book book = new Book();
//    book.setBid(150141318);//删除id为150141318的数据
//    try {
//      bookDao.del(book);
//    } catch (Exception e) {
//      e.printStackTrace();
//    }
//  }
  @Test
  public void testEdit() {
    Book book = new Book(150141318,"被修改了啊啊啊",999);
    try {
      bookDao.edit(book);
    } catch (Exception e) {
      e.printStackTrace();
  }
  }
}

可以看到我们添加了一条名字为"嘿嘿"的数据，效果图如下：

接着我们试着删除它，如下：

最后试着修改：

经过测试之后没问题，我们通用增删改也就编写完成了。

3.后台代码

新建一个BookAction类：

package com.Kissship.web;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.Kissship.dao.BookDao;
import com.Kissship.entity.Book;
import com.Kissship.util.PageBean;
import com.zking.framework.ActionSupport;
import com.zking.framework.ModelDriven;
public class BookAction extends ActionSupport implements ModelDriven<Book> {
  private Book book = new Book();
  private BookDao bookDao = new BookDao();
  // 查询--bookList.jsp
  public String list(HttpServletRequest req, HttpServletResponse resp) {
    PageBean pageBean = new PageBean();
    pageBean.setRequest(req);
    try {
      List<Book> lst = bookDao.list(book, pageBean);
      req.setAttribute("lst", lst);
      req.setAttribute("pageBean", pageBean);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return "list";
  }
  // 编辑界面跳转--bookEdit.jsp
  public String toEdit(HttpServletRequest req, HttpServletResponse resp) {
    try {
      if (book.getBid() != 0) {
        List<Book> lst = bookDao.list(book, null);
        req.setAttribute("lst", lst.get(0));
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return "toEdit";
  }
  // 增加--重定向到http://localhost:8080/mvc/book.action?methodName=list
  public String add(HttpServletRequest req, HttpServletResponse resp) {
    try {
      bookDao.add(book);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return "toList";
  } 
  // 删除
  public String del(HttpServletRequest req, HttpServletResponse resp) {
    try {
      bookDao.del(book);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return "toList";
  } 
  // 修改
  public String edit(HttpServletRequest req, HttpServletResponse resp) {
    try {
      bookDao.edit(book);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return "toList";
  } 
  @Override
  public Book getModel() {
    return book;
  }
}

在写完BookAction类之后把它的路径名放进我们的xml配置文件中，如下：

mvc.xml：

<?xml version="1.0" encoding="UTF-8"?>
<config>
  <action path="/book" type="com.Kissship.web.BookAction">
    <forward name="list" path="/bookList.jsp" redirect="false" />
    <forward name="toList" path="/book.action?methodName=list" redirect="true" />
    <forward name="toEdit" path="/bookEdit.jsp" redirect="false" />
  </action>
</config>

4.前端代码

在我们的后台代码写完之后，需要把我们的效果在浏览器上显示出来，也就需要我们完善前端的代码，如下：

copy我们之前写过的bookList.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
<%@ taglib uri="http://jsp.veryedu.cn" prefix="z"%> 
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<link
  href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
  rel="stylesheet">
<script
  src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
<title>书籍列表</title>
<style type="text/css">
.page-item input {
  padding: 0;
  width: 40px;
  height: 100%;
  text-align: center;
  margin: 0 6px;
}
.page-item input, .page-item b {
  line-height: 38px;
  float: left;
  font-weight: 400;
}
.page-item.go-input {
  margin: 0 10px;
}
</style>
</head>
<body>
  <form class="form-inline"
    action="${pageContext.request.contextPath }/book.action?methodName=list" method="post">
    <div class="form-group mb-2">
      <input type="text" class="form-control-plaintext" name="bname"
        placeholder="请输入书籍名称">
<!--      <input name="rows" value="20" type="hidden"> -->
<!-- 不想分页 -->
        <input name="pagination" value="false" type="hidden">
    </div>
    <button type="submit" class="btn btn-primary mb-2">查询</button>
    <a class="btn btn-primary mb-2" href="${pageContext.request.contextPath }/book.action?methodName=toEdit">新增</a>
  </form>
  <table class="table table-striped bg-success">
    <thead>
      <tr>
        <th scope="col">书籍ID</th>
        <th scope="col">书籍名</th>
        <th scope="col">价格</th>
        <th scope="col">操作</th>
      </tr>
    </thead>
    <tbody>
      <c:forEach  var="b" items="${lst }">
      <tr>
        <td>${b.bid }</td>
        <td>${b.bname }</td>
        <td>${b.price }</td>
        <td>
          <a href="${pageContext.request.contextPath }/book.action?methodName=toEdit&bid=${b.bid}">修改</a>
          <a href="${pageContext.request.contextPath }/book.action?methodName=del&bid=${b.bid}">删除</a>
        </td>
      </tr>
      </c:forEach>
    </tbody>
  </table>
  <!-- 这一行代码就相当于前面分页需求前端的几十行了 -->
  <z:page pageBean="${pageBean }"></z:page>
</body>
</html>

bookEdit：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>编辑界面</title>
</head>
<body>
<form action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'edit'}" method="post">
  编号:<input type="text" name="bid" value="${b.bid }"><br>
  名称:<input type="text" name="bname" value="${b.bname }"><br>
  价格:<input type="text" name="price" value="${b.price }"><br>
  <input type="submit"><br>
</form>
</body>
</html>

效果图：

最后自定义MVC增删改查(终极篇)就到这里，祝大家在敲代码的路上一路通畅!

感谢大家的观看 !

自定义MVC增删改查(终极篇)

1.框架配置

1.1将框架达成jar包，然后导入新工程，并且把框架的依赖jar包导入进去

1.2在这之后呢我们只需要导入其他的和依赖（助手类、baseDao······）

1.3框架的配置文件添加、以及web.xml的配置

2.通用增删改

3.后台代码

4.前端代码

热门文章

最新文章

相关课程

相关电子书

热门

活动广场

任务中心

开发者评测

高校计划

乘风者计划

训练营

阿里云MVP

话题

直播

下载

镜像站

技术资料

插件

自定义MVC增删改查(终极篇)

1.框架配置

1.1将框架达成jar包，然后导入新工程，并且把框架的依赖jar包导入进去

1.2在这之后呢我们只需要导入其他的和依赖（助手类、baseDao······）

1.3框架的配置文件添加、以及web.xml的配置

2.通用增删改

3.后台代码

4.前端代码

热门文章

最新文章

相关课程

相关电子书