Struts2写一个小项目

爱被打了一巴掌 2022-06-04 09:25 204阅读 0赞

写一个Struts2的增删改查的项目

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就以老师给的这道题目为例：

首先分析一下这道题目需要什么：

这道题目完成查询功能就可以了：

单条件查询就需要一个搜索框，写在view层（jsp页面）

多条件查询就需要多个搜索框了，

写一个类似这样的界面

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好的开始写这个页面：

代码如下：

<%@ taglib prefix="s"  uri="/struts-tags"%>
    
    <body>
    <div align='center'>
    <h2>单条件搜索</h2>
    <s:form action="Search" method="post">
    <s:textfield name="book.Name" label="图书名字"></s:textfield>
    <s:submit value="搜索"></s:submit>
    </s:form>
    </div>
    <div align='center'>
    <h2>多条件搜索</h2>
    <s:form action="MulSearch" method="post">
    <s:textfield name="book.ISBN" label="图书编号"></s:textfield>
    <s:textfield name="book.Name" label="图书名字"></s:textfield>
    <s:textfield name="book.Author" label="图书作者"></s:textfield>
    <s:submit value="搜索"></s:submit>
    </s:form>
    </div>
    <a href="BookList">全部书籍</a>
    </body>

写好这个就可以了，接下来我习惯写Model层

package com.zmy.model;
    
    public class Book {
    	private String bookISBN;
    	private String bookName;
    	private String bookAuthor;
    	
    	public String getBookISBN() {
    		return bookISBN;
    	}
    	public void setBookISBN(String bookISBN) {
    		this.bookISBN = bookISBN;
    	}
    	public String getBookName() {
    		return bookName;
    	}
    	public void setBookName(String bookName) {
    		this.bookName = bookName;
    	}
    	public String getBookAuthor() {
    		return bookAuthor;
    	}
    	public void setBookAuthor(String bookAuthor) {
    		this.bookAuthor = bookAuthor;
    	}
    }

把属性都封装了。

接下来写操作SearchDao

实现单条件和多条件查询

package com.zmy.dao;
    
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.ArrayList;
    
    import com.zmy.dbpool.*;
    import com.zmy.model.Book;
    
    public class SearchDao {
    	private Connection conn;
    	private Statement state;
    	private PreparedStatement pst;
    	private ResultSet rs;
    	private ArrayList<Book> books;
    	
    	public SearchDao(){
    		if(conn==null)
    		{
    			try
    			{
    				conn=Dbpool.getConnection();
    			}
    			catch(Exception e)
    			{
    				e.printStackTrace();
    			}
    		}
    	}
    	
    	
    	public ArrayList<Book> getBookByName(String bookName){
    		   books=new ArrayList<Book>();
    		   
    		   try {
    			   state=conn.createStatement();
    			   rs=state.executeQuery("select * from book where bookName='"+bookName+"'");
    			   while(rs.next())
    			   {
    				   Book book=new Book();
    				   book.setBookISBN(rs.getString(1));
    				   book.setBookName(rs.getString(2));
    				   book.setBookAuthor(rs.getString(3));
    				   books.add(book);
    			   }
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		   finally{
    				
    				try {
    					rs.close();
    					state.close();
    				} catch (SQLException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    			}
    		   return books; 
    	   }
    
    	public ArrayList<Book> getBookByMul(String bookISBN,String bookName,String bookAuthor){
    		   books=new ArrayList<Book>();
    		   
    		   try {
    			   state=conn.createStatement();
    			   rs=state.executeQuery("select * from book where bookName='"+bookName+"' and bookISBN='"+bookISBN+"' and bookAuthor='"+bookAuthor+"'");
    			   while(rs.next())
    			   {
    				   Book book=new Book();
    				   book.setBookISBN(rs.getString(1));
    				   book.setBookName(rs.getString(2));
    				   book.setBookAuthor(rs.getString(3));
    				   books.add(book);
    			   }
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		   finally{
    				try {
    					rs.close();
    					state.close();
    				} catch (SQLException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    			}
    		   return books; 
    	   }
    	
    	
       public ArrayList<Book> getBookList(){
    	   books=new ArrayList<Book>();
    	   
    	   try {
    		   state=conn.createStatement();
    		   rs=state.executeQuery("select * from book");
    		   while(rs.next())
    		   {
    			   Book book=new Book();
    			   book.setBookISBN(rs.getString(1));
    			   book.setBookName(rs.getString(2));
    			   book.setBookAuthor(rs.getString(3));
    			   books.add(book);
    		   }
    	} catch (SQLException e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    	   finally{
    			
    			try {
    				rs.close();
    				state.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    	   return books; 
       }
       
    }

这些就是三个查询，其他的改变sql语句就可以了。

接下来是重点说的，发现有很多同学在传值这一块有问题，有很多同学思维定式，struts2传值和servlet就不是一回事。

大家可以看我前面写的帖子。我使用域模式传值。

写控制层Action

package com.zmy.action;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import com.opensymphony.xwork2.ActionSupport;
    import com.zmy.dao.SearchDao;
    import com.zmy.model.Book;
    
    @SuppressWarnings("serial")
    public class SearchAction extends ActionSupport {
    	private List<Book> books;
    	private SearchDao searchDao;
    	private Book book;
    	
    	
    	public List<Book> getBooks() {
    		return books;
    	}
    	public void setBooks(List<Book> books) {
    		this.books = books;
    	}
    	public SearchDao getSearchDao() {
    		return searchDao;
    	}
    	public void setSearchDao(SearchDao searchDao) {
    		this.searchDao = searchDao;
    	}
    	public Book getBook() {
    		return book;
    	}
    	public void setBook(Book book) {
    		this.book = book;
    	}
    	public SearchAction()
    	{
    		searchDao=new SearchDao();
    	}
    
    	public String getAllBook()
    	{
    		this.books=searchDao.getBookList();
    		return SUCCESS;
    	}
    
    
    	public String getBookByBookName()
    	{
    		this.books=searchDao.getBookByName(book.getBookName());
    		return SUCCESS;
    	}
    	
    	public String getBookByMul()
    	{
    		books=searchDao.getBookByMul(book.getBookISBN(), book.getBookName(), book.getBookAuthor());
    		return SUCCESS;
    	}
    }

这就是他的控制层，通过调用searchDao（）得出结果。

再写的就是数据库连接程序：

package com.zmy.dbpool;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    
    public class Dbpool {
    	public static Connection getConnection(){
    		String driver="com.mysql.jdbc.Driver";
    		String url="jdbc:mysql://localhost/db_library?characterEncoding=utf8&zeroDateTimeBehavior=convertToNull";
    		Connection conn=null;
    		
    		try{
    			Class.forName(driver);
    			try{
    				conn=DriverManager.getConnection(url,"root",null);
    			}catch(SQLException e){
    				e.printStackTrace();
    			}
    		}catch(ClassNotFoundException e){
    			e.printStackTrace();
    		}
    		System.out.println("Successfully connected to the database");
    		return conn;
    	}
    }

建议大家每次写代码时都写一些提示性语句，这样就容易得出出问题的位置，方便排查。

到了这而之后就写配置文件：

struts.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE struts PUBLIC
    	"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    	"http://struts.apache.org/dtds/struts-2.3.dtd">
    
    <struts>
    
        <constant name="struts.enable.DynamicMethodInvocation" value="false" />
        <constant name="struts.devMode" value="true" />
    
        <package name="default" extends="struts-default">
        
        <action name="Search" class="com.zmy.action.SearchAction" method="getBookByBookName">
        	<result name="success">/bookList.jsp</result>
        </action>
    	
    	<action name="MulSearch" class="com.zmy.action.SearchAction" method="getBookByMul">
    			<result name="success">/bookList.jsp</result>
    	</action>
    	
    	<action name="BookList" class="com.zmy.action.SearchAction" method="getAllBook">  
    		    <result name="success">/bookList.jsp</result>
    	</action>
        </package>
    </struts>

这样就快接近尾声了

最后一步迭代输出

<%@ page language="java" contentType="text/html; charset=utf-8"
        pageEncoding="utf-8"%>
    <%@ taglib prefix="s" uri="/struts-tags" %>
    <!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=ISO-8859-1">
    <title>Insert title here</title>
    </head>
    <body>
    <table border="1">
    <tr bgcolor="#33ccff">
    <td>编号</td><td>书名</td><td>作者</td>
    </tr>
    <s:iterator value="books" status="st">
    <tr <s:if test="#st.odd">style="background-color:#bbbbbb"</s:if>>
    				<td align="center">
    					<s:property value="bookISBN"></s:property>
    				</td>
    				<td align="center">
    					<s:property value="bookName"></s:property>
    				</td>
    				<td align="center">
    					<s:property value="bookAuthor"></s:property>
    				</td>
    			</tr>
    </s:iterator>
    </table>
    </body>
    </html>

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这样整个流程就搞定了，当然我写的时候是没这么顺利的，出过一些问题，不过错误在控制台会爆出来的，

把错误改掉就可以了

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