[Java知识库] Struts的增删改查

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[Java知识库]Struts的增删改查

一.新建项目

创建一个 Maven项目，具体步骤见：Maven_m0_52681702的博客-CSDN博客一.本期内容为什么使用Maven:一个Java项目要依赖很多jar包，每次下载别人项目后到处是红，得自己一个个从网上下载需要的jar包，麻烦的很。但是如果你用了Maven，我就会有一个配置文件，文件里写清楚我这个项目需要哪个jar包，别人下载你的项目后背后的机制直接按图索骥把你想要的jar包下载下来。背后的机制是什么？就涉及到了仓库和配置文件问题。1、Maven简单介绍Apache Maven是个项目管理和自动构建工具，基于项目对象模型（POM）的概念。作用：完成项目的相关操作，如：编译https://blog.csdn.net/m0_52681702/article/details/120713096?spm=1001.2014.3001.5501

二.导入pom.xml的相关依赖

1.web.xml改成3.1的版本

2.导入struts相关的配置文件

3.jdk1.5改为1.8? ?web2.3改为3.1

4.pom.xml需要添加plugins>plugin

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.pjl</groupId>
  <artifactId>T269_struts</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>T269_struts Maven Webapp</name>
  <url>http://maven.apache.org</url>
   <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.plugin.version>3.7.0</maven.compiler.plugin.version>

    <!--添加jar包依赖-->
    <!--mysql-->
    <mysql.version>8.0.19</mysql.version>
    <!--5.其他-->
    <junit.version>4.12</junit.version>
    <servlet.version>4.0.0</servlet.version>
    <jackson.version>2.9.3</jackson.version>
    <jstl.version>1.2</jstl.version>
    <standard.version>1.1.2</standard.version>
    <tomcat-jsp-api.version>8.0.47</tomcat-jsp-api.version>
    <commons-beanutils.version>1.9.3</commons-beanutils.version>
    <dom4j.version>1.6.1</dom4j.version>
    <jaxen.version>1.1.6</jaxen.version>
    <struts2-core.version>2.5.13</struts2-core.version>
    

  </properties>
  
  <dependencies>
    <dependency>
			<groupId>org.apache.struts</groupId>
			<artifactId>struts2-core</artifactId>
			<version>${struts2-core.version}</version>
		</dependency>
    <dependency>
      <groupId>jaxen</groupId>
      <artifactId>jaxen</artifactId>
      <version>${jaxen.version}</version>
    </dependency>

    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>${dom4j.version}</version>
    </dependency>


    <dependency>
      <groupId>commons-beanutils</groupId>
      <artifactId>commons-beanutils</artifactId>
      <version>${commons-beanutils.version}</version>
    </dependency>

    <!--mysql-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>${junit.version}</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>${servlet.version}</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>${jackson.version}</version>
    </dependency>

    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>${jstl.version}</version>
    </dependency>
    <dependency>
      <groupId>taglibs</groupId>
      <artifactId>standard</artifactId>
      <version>${standard.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-jsp-api</artifactId>
      <version>${tomcat-jsp-api.version}</version>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.10</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>com.belerweb</groupId>
      <artifactId>pinyin4j</artifactId>
      <version>2.5.0</version>
    </dependency>

    <dependency>
      <groupId>com.github.davidcarboni</groupId>
      <artifactId>encrypted-file-upload</artifactId>
      <version>2.1.0</version>
    </dependency> 
  </dependencies>
  
  <build>
    <finalName>T269_struts</finalName>
    <plugins>
    <plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.7.0</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
					<encoding>UTF-8</encoding>
				</configuration>
			</plugin>
    </plugins>
  </build>
</project>

三.导入帮助类以及tld文件

如图：

四.Struts增删改查的编码

思路步骤：1.实体类 2.dao类 3.子控制器

本节课的内容区别在于：BaseAction（优化BaseAction）

? ? ? ? ? ?1.编码习惯问题，容易出现大小写配置错误

? ? ? ? ? ?2.每个子控制器都要实现对应接口，拿到request和respons对象

? ? ? ? ? ?3.向前端页面反馈的数据变量不统一

package com.pjl.crud.web;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;

import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

public abstract class BaseAction<T> extends ActionSupport implements ServletRequestAware,ServletResponseAware,ModelDriven<T>{
protected HttpServletRequest req;
protected HttpServletResponse resp;
protected HttpSession session;
protected static final String LIST = "list";
protected static final String TOLIST = "toList";
protected static final String TOEdit = "toEdit";

@Override
public void setServletResponse(HttpServletResponse response) {
	this.resp=response;
	
}
@Override
public void setServletRequest(HttpServletRequest request) {
	this.req=request;
	this.session=request.getSession();
	
}
//3.向前端页面反馈的数据变量不统一
protected Object result;
protected String msg;
protected int code;

public Object getResult() {
	return result;
}
public void setResult(Object result) {
	this.result = result;
}
public String getMsg() {
	return msg;
}
public void setMsg(String msg) {
	this.msg = msg;
}
public int getCode() {
	return code;
}
public void setCode(int code) {
	this.code = code;
}


}

第一步：创建实体类Clz

package com.pjl.crud.entity;

public class Clz {
 private int cid;
 private String cname;
 private String cteacher;
 private String pic;
public int getCid() {
	return cid;
}
public void setCid(int cid) {
	this.cid = cid;
}
public String getCname() {
	return cname;
}
public void setCname(String cname) {
	this.cname = cname;
}
public String getCteacher() {
	return cteacher;
}
public void setCteacher(String cteacher) {
	this.cteacher = cteacher;
}
public String getPic() {
	return pic;
}
public void setPic(String pic) {
	this.pic = pic;
}
@Override
public String toString() {
	return "Clz [cid=" + cid + ", cname=" + cname + ", cteacher=" + cteacher + ", pic=" + pic + "]";
}

 
}

第二步：Dao层ClzDao

package com.pjl.crud.dao;

import java.util.List;

import com.pjl.crud.entity.Clz;
import com.pjl.crud.util.BaseDao;
import com.pjl.crud.util.PageBean;

public class ClzDao extends BaseDao<Clz>{
  
	
	public List<Clz> list(Clz clz, PageBean pageBean) throws Exception {
        String sql = "select * from t_struts_class where 1=1 ";
		int cid=clz.getCid();
		if(cid !=0) {
			sql += " and cid ="+cid;
		}
        return super.executeQuery(sql,Clz.class, pageBean);
	}
	
	public void add(Clz t) throws Exception {
        String sql = "insert into t_struts_class values(?,?,?,?)";
		super.executeUpdate(sql,t,new String[] {"cid","cname","cteacher","pic"});
	}
	
	public void edit(Clz t) throws Exception {
        String sql = "update t_struts_class set cname=?,cteacher=?,pic=? where cid=?";
		super.executeUpdate(sql,t,new String[] {"cname","cteacher","pic","cid"});
	}
	
	public void del(Clz t) throws Exception {
        String sql = "delete t_truts_class where cid=?";
		super.executeUpdate(sql,t,new String[] {"cid"});
	}
	
}

第三步：子控制器ClzAction（web层）

package com.pjl.crud.web;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.ActionSupport;
import com.pjl.crud.dao.ClzDao;
import com.pjl.crud.entity.Clz;
import com.pjl.crud.util.PageBean;

public class ClzAction extends BaseAction<Clz>{
  private Clz clz=new Clz(); 
  private ClzDao clzDao =new ClzDao();
/**
 * 查询班级列表
 * @return
 * @throws Exception
 */
  public String list() throws Exception {
	  //首先对pagebean进行初始化
	  PageBean pageBean = new PageBean();
	  pageBean.setRequest(req);
	  this.result=this.clzDao.list(clz, pageBean);
	  //返回，从父层定义好的
	  this.req.setAttribute("result",result);
	  this.req.setAttribute("pageBean",pageBean);
	  return LIST;
}
/**
 * 跳转新增/修改界面
 * @return
 * @throws Exception
 */
public String toEdit() throws Exception {
	//作判断
	int cid=clz.getCid();
	//如果传了cid,则跳修改界面
	if(cid != 0) {
		this.result=this.clzDao.list(clz, null).get(0);
		this.req.setAttribute("result",result);
	}
	return TOEdit;
}
/**
 * 往数据库新增数据
 * @return
 * @throws Exception
 */
public String add() throws Exception {
	this.clzDao.add(clz);
	return TOLIST;
}
/**
 * 修改数据
 * @return
 * @throws Exception
 */
public String edit() throws Exception {
	this.clzDao.edit(clz);
	return TOLIST;
}
/**
 * 删除数据
 * @return
 * @throws Exception
 */
public String del() throws Exception {
	this.clzDao.del(clz);
	return TOLIST;
}

@Override
public Clz getModel() {
	return clz;
}



}

第四步：所需界面

ClzEdit.jsp

<%@ page language='java' contentType='text/html; charset=UTF-8'
	pageEncoding='UTF-8'%>
	<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
	<%@ taglib prefix="z" uri="http://jsp.veryedu.cn"%>
<!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>新增/修改书籍列表</title>

</head>
<body>
	<form class="form-inline"
		action="${pageContext.request.contextPath }/sy/Clz_${empty result ? 'add' : 'edit'}.action" method="post">
		cid:<input type="text" name="cid" value="${result.cid }"><br>
		cname:<input type="text" name="cname" value="${result.cname }"><br>
		cteacher:<input type="text" name="cteacher" value="${result.cteacher}"><br>
		<input type="submit">
	</form>

</body>
</html>

ClzList.jsp

<%@ page language='java' contentType='text/html; charset=UTF-8'
	pageEncoding='UTF-8'%>
	<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
	<%@ taglib prefix="z" uri="http://jsp.veryedu.cn"%>
<!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="${pageContext.request.contextPath }/sy/Clz_list.action" method='post'>
		<div class='form-group mb-2'>
			<input type='text' class='form-control-plaintext' name='bname'
				placeholder='请输入书籍名称'>
				<!-- 不分页 -->
			<!-- 	<input name="rows" value="false" type="hidden"> -->
		</div>
		<button type='submit' class='btn btn-primary mb-2'>查询</button>
		<a  class='btn btn-primary mb-2' href="${pageContext.request.contextPath }/sy/Clz_toEdit.action">新增</a>
	</form>

	<table class='table table-striped bg-success'>
		<thead>
			<tr>
				<th scope='col'>ID</th>
			    <th scope='col'>班级名字</th>
				<th scope='col'>教员</th>
				<th scope='col'>图片</th>
				<th scope='col'>操作</th>
			</tr>
		</thead>
		<tbody>
		<c:forEach var="b" items="${result }">
		<tr>
				<td>${b.cid }</td>
				<td>${b.cname }</td>
				<td>${b.cteacher }</td>
				<td>${b.pic }</td>
				<td>
				<a href="${pageContext.request.contextPath }/sy/Clz_toEdit.action?cid=${b.cid}">>修改</a>
				<a href="${pageContext.request.contextPath }/sy/Clz_del.action?cid=${b.cid}">>删除</a>

				
				</td>
			</tr>
		</c:forEach>
			

		</tbody>
	</table>
	<!-- 这一行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>

展示效果：?