struts的增删改查-白红宇

struts的增删改查

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发布时间：2019-06-14

本文共 10381 字，大约阅读时间需要 34 分钟。

1、导入相关的pom依赖（struts、自定义标签库的依赖）

</dependency>

<groupId>taglibs</groupId>

<artifactId>standard</artifactId>

</dependency>

<groupId>org.apache.tomcat</groupId>

<artifactId>tomcat-jsp-api</artifactId>

</dependency>

2、分页的tag类导入、z.tld、完成web.xml的配置

pageTag.java

package com.huang.crud.tag;import java.io.IOException;import java.util.Map;import java.util.Map.Entry;import javax.servlet.jsp.JspException;import javax.servlet.jsp.JspWriter;import javax.servlet.jsp.tagext.BodyTagSupport;import com.huang.crud.util.PageBean;public class PageTag extends BodyTagSupport {        private static final long serialVersionUID = -8476740758233598045L;    private PageBean pageBean;        @Override    public int doStartTag() throws JspException {        JspWriter out = pageContext.getOut();        try {            out.write(toHTML());        } catch (IOException e) {            e.printStackTrace();        }        return super.doStartTag();    }    public String toHTML() {//    pageBean=new PageBean();    StringBuffer sb=new StringBuffer();    //下一次请求提交到后台的表单html代码拼接    sb.append("
     ");    sb.append("");    sb.append("");    sb.append("
     
      ");    Map
      
        paramMap = pageBean.getParameterMap();    if(paramMap!=null&&paramMap.size()>0) {        for(Entry
       
         entry:paramMap.entrySet()) {            if(!"page".equals(entry.getKey())) {                for(String val:entry.getValue()) {                    sb.append("
         value='"+val+"'");                }            }        }    }    sb.append("
        ");    sb.append("");            //分页条html代码拼接    sb.append("
        
         ");    sb.append(" 每页"+pageBean.getRows()+"条，共"+pageBean.getTotal()+"条，第"+pageBean.getPage()+"页，共"+pageBean.getMaxPage()+"页  ");    sb.append(" 
         首页  
         
          上一页  
          
           下一页  
           
            尾页  
              
            
             Go"); sb.append(" 
            
           
          
         
        
");            //分页所需要调用的js代码    sb.append("
        ");            return sb.toString();    }    public PageBean getPageBean() {        return pageBean;    }    public void setPageBean(PageBean pageBean) {        this.pageBean = pageBean;    }}

z.tid


     
       
      
       dj 1.1 core library
        
      
       dj core
        
      
       1.1
        
      
       d
        
      
       /huang
       
          
       
        page
           
       
        com.huang.crud.tag.PageTag
           
       
        JSP
           
               
        
         pageBean
                
        
         true
                
        
         true

web.xml


       
      
       Archetype Created Web Application
           
            
       
        encodingFiter
             
       
        com.huang.crud.util.EncodingFiter
         
        
            
       
        encodingFiter
             
       
        /*
         
         
        
       
        struts2
           
       
        org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter
           
        
        
       
        struts2
         
       
        *.action

3、dao层去访问数据

ClazzDao.java

package com.huang.crud.dao;import java.sql.SQLException;import java.util.List;import com.huang.crud.entity.Clazz;import com.huang.crud.util.BaseDao;import com.huang.crud.util.PageBean;import com.huang.crud.util.StringUtils;public class ClazzDao extends BaseDao
     
       {    public List
      
        list(Clazz clazz,PageBean pageBean) throws InstantiationException, IllegalAccessException, SQLException{        String sql= "select * from t_struts_class where true ";        String cname= clazz.getCname();        int cid=clazz.getCid();         if(cid!=0) {             sql +=" and cid ="+cid;          }                if(StringUtils.isNotBlank(cname)) {            sql +=" and cname like '%"+cname+"%'";        }                return super.executeQuery(sql,Clazz.class , pageBean);            }        public int add(Clazz clazz) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException, InstantiationException {        String sql= "insert into t_struts_class values(?,?,?,?)";        return super.executeUpdate(sql,new String[] {"cid","cname","cteacher","pic"}, clazz);    }            public int del(Clazz clazz) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException, InstantiationException {        String sql= "delete from t_struts_class where cid=?";        return super.executeUpdate(sql,new String[] {"cid"}, clazz);    }        public int edit(Clazz clazz) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException, InstantiationException {        String sql= "update  t_struts_class set cname=?,cteacher=?,pic=? where cid=?";        return super.executeUpdate(sql,new String[] {"cname","cteacher","pic","cid"}, clazz);    }}

BaseDao.java

package com.huang.crud.util;import java.lang.reflect.Field;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import com.huang.crud.entity.Clazz;public class BaseDao
     
       {            /**     * T=Student.class     *      * @param sql     决定查询哪张表的数据     * @param clz    查询出来的数据封装到哪个实体类中     * @param pageBean    决定是否分页     * @return     * @throws      * @throws InstantiationException      * @throws SQLException      * @throws IllegalAccessException      * @throws IllegalArgumentException      * @throws InstantiationException      */    public List
      
        executeQuery(String sql,Class clz,PageBean pageBean) throws SQLException, IllegalArgumentException, IllegalAccessException, InstantiationException {        List
       
         ls=new ArrayList<>();        Connection con=DBAccess.getConnection();        PreparedStatement ps = null;        ResultSet rs = null;                if(pageBean!=null && pageBean.isPagination()) {            //该分页了            String countSql=getCountSql(sql);//获取符合记录的行数的Sql语句            try {                ps=con.prepareStatement(countSql);            } catch (SQLException e) {                e.printStackTrace();            }            try {                rs=ps.executeQuery();            } catch (SQLException e) {                e.printStackTrace();            }            if(rs.next()) {                pageBean.setTotal(rs.getLong(1)+"");//给pageBean的总页数赋值            }                        String pageSql=getPageSql(sql,pageBean);//拼接上符合条件的分页查询sql语句            ps=con.prepareStatement(pageSql);            rs=ps.executeQuery();        }        else {             ps = con.prepareStatement(sql);             rs = ps.executeQuery();        }                try {            while (rs.next()) {                //            ls.add(new Book(rs.getInt("bid"),                //                    rs.getString("bname"),                //                    rs.getFloat("price")));                /**                 * 1、创建了一个book对象                 * 2、从ResultSet结果集中获取值放入Book对象属性中                 *         2.1获取到book的属性对象                 *         2.2给属性对象赋值                 * 3、将已经有值的Book对象放进list集合中                 *                  */                T t = (T) clz.newInstance();                Field[] fields = clz.getDeclaredFields();                for (Field field : fields) {                    field.setAccessible(true);                    field.set(t, rs.getObject(field.getName()));                }                ls.add(t);            }         } finally {            DBAccess.close(con,ps,rs);        }        return ls;    }        /**     * 将原生sql拼接出符合条件的某一页的数据查询     * @param sql     * @return     */    private String getPageSql(String sql,PageBean pageBean) {        return sql + " limit "+pageBean.getStartIndex()+","+pageBean.getRows();    }    /**     * 用原生sql拼接出查询符合条件的记录数     * @param sql     * @return     */    private String getCountSql(String sql) {        return "select count(1) from ("+sql+") t";    }            /**     * 通用的增删改方法     * @param sql    增删改的sql语句     * @param attrs    ？所代表的实体类的属性     * @param t        实体类的实例     * @return     * @throws SQLException     * @throws NoSuchFieldException     * @throws SecurityException     * @throws IllegalArgumentException     * @throws IllegalAccessException     * @throws InstantiationException      */    public int executeUpdate(String sql, String[] attrs, T t) throws SQLException, NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, InstantiationException {        Connection con = DBAccess.getConnection();        PreparedStatement pst = con.prepareStatement(sql);        for (int i = 0; i < attrs.length; i++) {            Field field = t.getClass().getDeclaredField(attrs[i]);            field.setAccessible(true);            pst.setObject(i+1, field.get(t));        }        return pst.executeUpdate();    }}

4、在struts_sy.xml进行配置

struts_sy.xml


     
         
            
              
        
         /clzList.jsp
               
        
         /clzEdit.jsp
               
        
         /clz_list

5、写jsp

clzList.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>    <%@ taglib uri="/huang" prefix="d" %>
     主界面小说目录
    
    
     
              书名：
       
                  
          
     
    增加    
                 
     
     
                                         编号                     班级名称                     班级图片                     操作                
                                       ${b.cid }                         ${b.cname }                         ${b.cteacher }                         ${b.pic }                                             修改                     删除                    文件上传

clzEdit.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>
     Insert title here
     
       cid:
       cname:
        cteacher: