使用MyEclipse中servlet对SQL Server 2008的CRUD

1、在MyEclipse下建立Web Project，找到根目录建立Database文件夹和Doc文件夹，Database用于保存数据库信息，Doc用于保存数据库表信息。

2、打开SQL Server 2008 ，新建数据库CRUD，将路径添加到Database文件夹下。

3、写SQL语句添加数据库表，保存在Doc文件夹下。到这对数据库的操作就完成了。

CREATE TABLE Student(
  sno nvarchar(10) not null,
  sname nvarchar(10) null,
  constraint PK_Student primary key(sno)
);
insert Student values('001','张三');
insert Student values('002','李四');
insert Student values('003','王五');
insert Student values('004','赵六');

4、将sqljdbc4.jar（没有可在网上下载）拷贝到WEB-INF下的lib文件夹下，然后建立StudentList.jsp，输入以下代码：

<%@  import="java.sql.*" %>
<%
   Connection con=null;
   Statement stmt=null;
   ResultSet rs=null;
   Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
   con=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;          DatabaseName=CRUD","sa","123");
   String SQL="SELECT * FROM Student";
   stmt=con.createStatement();
   rs=stmt.executeQuery(SQL);
%>
  <center>    
        学生列表
    <br>
    <br>
    <a href="StudentAdd.html">添加</a>
    <br>
    <br>
    
    <table border="1" cellspacing="0" cellpadding="4">
      <tr>
         <th>学号</th><th>姓名</th><th>操作</th>
      </tr>
    <%while (rs.next()) { %>
      <tr>
        <td><%=rs.getString("sno") %></td>
        <td><%=rs.getString("sname") %></td>
        <td>
    	<a href="StudentEdit.jsp?sno=<%=rs.getString("sno") %>" >编辑</a> 
    	<a href="servlet/DeleteStudent.do?sno=<%=rs.getString("sno") %>" >删除</a> </td>
      </tr>
    <% } %>
    </table>
    <br>
    
    <br>
    <a href="index.jsp">返回</a>
    </center>

　　

5、建立Package“com.langguojie.CRUD.servlet”，然后建立servlet“AddStudent.java”只选择“doPost()”函数即可。添加如下代码：

        import java.sql.*;
        // 获取数据
	request.setCharacterEncoding("utf-8");
	String strStudentSno = "";
	String strStudentSname = "";
	strStudentSno = request.getParameter("sno");
	strStudentSname = request.getParameter("sname");
				
	// 添加数据
	Connection con = null;    
	Statement stmt = null;    
				
        String url = "jdbc:sqlserver://127.0.0.1:1433;databaseName=CRUD;
        user=sa;password=123";//sa身份连接	
        try
	{
	      Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); 
	      con = DriverManager.getConnection(url);  
	      String strSql = "insert into Student values('" + strStudentSno + "','" + strStudentSname + "')";    
	      stmt = con.createStatement();  
	      stmt.execute(strSql);
	}
	catch (Exception e) 
	{
		response.setContentType("text/html");
		response.setCharacterEncoding("utf-8");
		PrintWriter out = response.getWriter();
		out.println("<center><br><br>添加失败,学号:" + strStudentSno);
		out.println("<br><br><a href='../StudentList.jsp'>返回</a></center>");
		out.close();
		return;
	}
						
	// 跳转
	response.sendRedirect("../StudentList.jsp");

　　

6、建立StudentAdd.html，添加如下代码：

<center>
  <br><br>添加学生<br>
    <form name="f1" id="f1" action="servlet/AddStudent.do" method="post">
      <table border="0">
        <tr>
          <td>学号:</td>
          <td><input type="text" name="sno"></td>
        </tr>
        <tr>
          <td>姓名:</td>
          <td><input type="text" name="sname"></td>
        </tr> 
        <tr>
          <td colspan="2" align="center"><input type="submit" value=" 确定 " ></td>
        </tr>
      </table>
    </form>
</center>

　　

7、按照步骤5添加servlet“EditStudent.java”和“DeleteStudent.java”

代码如下：

                EditStudent.java
                // 获取数据
		request.setCharacterEncoding("utf-8");
		String strStudentSno = "";
		strStudentSno = request.getParameter("sno");
		String strStudentSname = "";
		strStudentSname = request.getParameter("sname");
		
		// 删除数据
		Connection con = null;    
		Statement stmt = null;    
		ResultSet rs = null;  
		
		String url = "jdbc:sqlserver://127.0.0.1:1433;databaseName=CRUD;user=sa;password=123";//sa身份连接
		
		try
		{
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); 
			con = DriverManager.getConnection(url);  
			
			String strSql = "update Student set sname = '"+strStudentSname+"' where sno= " + strStudentSno + " ";    
			stmt = con.createStatement();  
			stmt.execute(strSql);
		}
		catch (Exception e) 
		{
			response.setContentType("text/html");
			response.setCharacterEncoding("utf-8");
			PrintWriter out = response.getWriter();
			out.println("编辑失败,学号:" + strStudentSno+"!");
			out.close();
			return;
		}
				
		// 跳转
		response.sendRedirect("../StudentList.jsp");

               DeleteStudent.java:
               // 获取数据
		request.setCharacterEncoding("utf-8");
		String strStudentSno = "";
		strStudentSno = request.getParameter("sno");
				
		// 删除数据
		Connection con = null;    
		Statement stmt = null;    
		ResultSet rs = null;  
				
		String url = "jdbc:sqlserver://127.0.0.1:1433;databaseName=CRUD;user=sa;password=123";//sa身份连接
				
		try
		{
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); 
			con = DriverManager.getConnection(url);  
					
			String strSql = "delete from Student where sno='" + strStudentSno + "'";    
			stmt = con.createStatement();  
			stmt.execute(strSql);
		}
		catch (Exception e) 
		{
			response.setContentType("text/html");
			response.setCharacterEncoding("utf-8");
			PrintWriter out = response.getWriter();
			out.println("删除失败,学号:" + strStudentSno+"!");
			out.close();
			return;
		}
						
		// 跳转
		response.sendRedirect("../StudentList.jsp");

　　

8、StudentEdit.jsp所对应的代码：

 <%@  import="java.sql.*" %>
  <%
	Connection con = null;    
	Statement stmt = null;    
	ResultSet rs = null;  
	
	String url = "jdbc:sqlserver://127.0.0.1:1433;databaseName=CRUD;user=sa;password=123";//sa身份连接
	
	Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); 
	con = DriverManager.getConnection(url);  
	stmt = con.createStatement();  
	
	request.setCharacterEncoding("utf-8");
	String strsno = "";
	strsno = request.getParameter("sno");
	String SQL = "SELECT * FROM Student where sno='" + strsno + "'";    
	rs = stmt.executeQuery(SQL);    
%>
<center>

<%if(rs.next()==true){ %>
	
  	<br><br>编辑学生信息<br>
    <form name="f1" id="f1" action="servlet/EditStudent.do" method="post">
      <table border="0">
        <tr>
          <td>学号:</td>
          <td><input type="text" readonly="readonly" name="sno" value="<%=rs.getString("sno") %>"> 学号不允许编辑</td>
        </tr>
        <tr>
          <td>姓名:</td>
          <td><input type="text" name="sname" value="<%=rs.getString("sname") %>"></td>
        </tr> 
        <tr>
          <td colspan="2" align="center"><input type="submit" value=" 确定 " ></td>
        </tr>
      </table>
    </form>
<%} else { %>
<br><br>编辑学生信息<br><br>
学号为<%=strsno %>的学生数据在数据库中不存在!<br><br>
<a href="StudentList.jsp">返回</a>
<%} %>
</center>

　　

9、运行结果截图：

查询界面：

添加界面：学号：005 姓名：郎国杰

添加成功界面：

编辑界面：将“郎国杰”改写成“langguojie”

编辑成功：

删除结果：

10、总结：

使用servlet对数据库的增删改查（CRUD）可以方便用户的操作，更具有规范性，可以避免代码泄露问题。这一部分是编辑网站以及开发网页的基础内容。