JavaWeb应用实例:用servlet实现oracle 基本增删改查

2019-11-26 13:16:52

字体：大中小

来源：转载

供稿：网友

很久没有写博客了，可能是太懒散，不愿意把时间花在这上面，可是我心里还是知道写博客的重要性的，所以从今天开始，我将与大家分享一下我学Java WEB写的一些小实例，我个人是不太喜欢书本上的晦涩的概念的，所以我花了更多的时间在一些应用实例上，我觉得这样的学习方式很适合我，由简到繁，由浅入深

废话不多话，开始我们的第一个实例：

servlet实现Oracle 基本增删改查

开发环境：JDK7 +Myeclipse10+tomcat7.0+oracle 11g

首先附上数据库创建脚本：

create table student( id VARCHAR2(50) PRIMARY KEY NOT NULL, name varchar2(50) NOT NULL, calssGrent varchar2(50) NOT NULL , result varchar(12) NOT NULL ); insert into student(id,name,calssGrent,result) values(perseq.nextval,'张三','33','98')

下图为代码结构图和功能演示界面做的比较糟糕只为实现功能：

MMC_01.Java

页面 //主界面提供添加，修改删除的方法

package org.lsy.servlet;  import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement;  import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  import oracle.jdbc.oracore.TDSPatch;  public class MMC_01 extends HttpServlet {   // 驱动程序就是之前在classpath中配置的jdbc的驱动程序的jar包中    // 连接地址是由各个数据库生产商单独提供的，所以需要单独记住   public static final String DBURL = "jdbc:oracle:thin:@localhost:1521:LIUSY";   // 连接数据库的用户名   public static final String DBUSER = "scott";   // 连接数据库的密码   public static final String DBPASS = "tiger";    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException   {     //设置请求和响应的编码 ，不然页面上容易出现乱码     request.setCharacterEncoding("UTF-8");     response.setCharacterEncoding("UTF-8");         response.setContentType("text/html;UTF-8");     //输出流     PrintWriter out = response.getWriter();     //数据库连接代码     try     {       Connection conn = null; // 表示数据库的连接的对象       Statement stmt = null; // 表示数据库的更新操作       String sql="insert into student(id,name,calssGrent,result) values('67','刘12宇','33','98')";       System.out.println(sql) ;       // 1、使用Class类加载驱动程序       Class.forName("oracle.jdbc.driver.OracleDriver");       // 2、连接数据库       conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);       // 3、Statement接口需要通过Connection接口进行实例化操作       stmt = conn.createStatement();       //用 rs获取查询结果 ，这里的SQL语句最好不要用* 我的字段比较少所以就偷一下懒，－，－       ResultSet rs=stmt.executeQuery("select *from student");       out.println("<!DOCTYPE HTML PUBLIC /"-//W3C//DTD HTML 4.01 Transitional//EN/">");       out.println("<HTML>");       out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");       out.println(" <BODY>");       //输出表头部分       out.print("<table align='center' border='1'><tr><td>姓名" +       "</td><td>班级</td><td>成绩</td><td>修改</td><td>删除</td></tr>");       while(rs.next())       {         //获取数据库中的ID         String id=rs.getString("id");         //输出一列元素         out.print("<tr><td>"+rs.getString("name")         +"</td><td>"+rs.getString("calssGrent")+"" +         "</td><td>"+rs.getString("result")+"</td>" +         "<td><a href='UpdatePage?id="+id+"'>修改</a></td>" +         "<td><a href='delete?id="+id+"'> 删除 </a></td></tr>");                }       out.println("<td><a href=AddPage>添加数据</a></td>");       out.println(" </BODY>");       out.println("</HTML>");        conn.close();            }     catch (Exception e)     {       e.printStackTrace();     }     out.flush();     out.close();   }  }

UpdatePage.java //获取要修改的数据，并把修改过的数据提交给Update

package org.lsy.servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement;  import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  import com.sun.crypto.provider.RSACipher;  public class UpdatePage extends HttpServlet {   // 连接地址是由各个数据库生产商单独提供的，所以需要单独记住     public static final String DBURL = "jdbc:oracle:thin:@localhost:1521:LIUSY";     // 连接数据库的用户名     public static final String DBUSER = "scott";     // 连接数据库的密码     public static final String DBPASS = "tiger";    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException   {     String id=request.getParameter("id");     //设置请求和响应的编码 ，不然页面上容易出现乱码     request.setCharacterEncoding("UTF-8");     response.setCharacterEncoding("UTF-8");      response.setContentType("text/html;UTF-8");     PrintWriter out = response.getWriter();     try     {       Connection conn = null; // 表示数据库的连接的对象       Statement stmt = null; // 表示数据库的更新操作       // 1、使用Class类加载驱动程序       Class.forName("oracle.jdbc.driver.OracleDriver");       // 2、连接数据库       conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);       // 3、Statement接口需要通过Connection接口进行实例化操作       stmt = conn.createStatement();       //用 rs获取查询结果 ，这里的SQL语句最好不要用* 我的字段比较少所以就偷一下懒，－，－       ResultSet rs=stmt.executeQuery("select *from student where id='"+id+"'");       while (rs.next())       {       out.println("<!DOCTYPE HTML PUBLIC /"-//W3C//DTD HTML 4.01 Transitional//EN/">");       out.println("<HTML>");       out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");       out.println(" <BODY>");       //输入成绩的表单，提交至Update       out.print(" <form action='Update' method='post'> ");       out.print("<table align='center'> <tr><td>姓名：<input type='text' value='"+rs.getString("name")+"'

      name='name' size=20 ></td></tr>");       out.print("<tr><td>班级：<input type='text' value='"+rs.getString("calssGrent")+"' name='grent' size=20></td></tr>");       out.print("<tr><td>成绩：<input type='text' value='"+rs.getString("result")+"' name='result' size=20></td></tr>");         //为了作为查询数据库的条件 ，这里要把ID传过去       out.print("<input type='hidden' value='"+id+"' name='id'>");       out.print("<tr><td><input type='submit' value='修改'><input type='reset' value='重置'></td></tr></table></form>");       out.print(" </BODY>");       out.println("</HTML>");       }       out.flush();       out.close();     }     catch (Exception e) {       e.printStackTrace();// TODO: handle exception     }     }  }

Update.java 接收要修改的数据，并更新数据库

package org.lsy.servlet;  import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement;  import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  public class Update extends HttpServlet {   // 驱动程序就是之前在classpath中配置的jdbc的驱动程序的jar包中    // 连接地址是由各个数据库生产商单独提供的，所以需要单独记住   public static final String DBURL = "jdbc:oracle:thin:@localhost:1521:LIUSY";   // 连接数据库的用户名   public static final String DBUSER = "scott";   // 连接数据库的密码   public static final String DBPASS = "tiger";    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException   {     try          {       request.setCharacterEncoding("UTF-8");       response.setCharacterEncoding("UTF-8");        response.setContentType("text/html;UTF-8");       PrintWriter out = response.getWriter();        Connection conn = null; // 表示数据库的连接的对象       Statement stmt = null; // 表示数据库的更新操作       //获取表单提交的参数       String id=request.getParameter("id");       System.out.println(id);       String name=request.getParameter("name");       String grent=request.getParameter("grent");       String result=request.getParameter("result");       //更新SQL       String sqlString="update student set name='"+name+"' ," +           "calssGrent='"+grent+"',result='"+result+"' where id='"+id+"' ";        // 1、使用Class类加载驱动程序       Class.forName("oracle.jdbc.driver.OracleDriver");       // 2、连接数据库       conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);       // 3、Statement接口需要通过Connection接口进行实例化操作       stmt = conn.createStatement();       int pd=stmt.executeUpdate(sqlString);       if(pd!=0)       {       out.println("<!DOCTYPE HTML PUBLIC /"-//W3C//DTD HTML 4.01 Transitional//EN/">");       out.println("<HTML>");       out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");       out.println(" <BODY>");       out.print(" 更新成功<br><a href=MMC_01>查看列表</a> ");       out.println(" </BODY>");       out.println("</HTML>");       }       out.flush();       out.close();       stmt.close();       conn.close();     }     catch (Exception e)     {       // TODO: handle exception     }   }   public void doPost(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException   {     doGet(request, response);   }  }

addPage .java，添加数据页面

package org.lsy.servlet;  import java.io.IOException; import java.io.PrintWriter;  import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  public class AddPage extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException   {     //设置请求和响应的编码 ，不然页面上容易出现乱码     request.setCharacterEncoding("UTF-8");     response.setCharacterEncoding("UTF-8");      response.setContentType("text/html;UTF-8");     PrintWriter out = response.getWriter();     out.println("<!DOCTYPE HTML PUBLIC /"-//W3C//DTD HTML 4.01 Transitional//EN/">");     out.println("<HTML>");     out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");     out.println(" <BODY>");     //输入成绩的表单，提交至add     out.print(" <form action='Add' method='post'> ");     out.print("<table align='center'> <tr><td>姓名：<input type='text' name='name' size=20 ></td></tr>");     out.print("<tr><td>班级：<input type='text' name='grent' size=20></td></tr>");     out.print("<tr><td>成绩：<input type='text' name='result' size=20></td></tr>");      out.print("<tr><td><input type='submit' value='添加'><input type='reset' value='重置'></td></tr></table></form>");     out.println("<tr><td><a href=MMC_01>查看列表</a></td></tr>");     out.println(" </BODY>");     out.println("</HTML>");     out.flush();     out.close();   }  }

add 接收addpage传来的传，更新数据库

package org.lsy.servlet;  import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Statement;  import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  import com.sun.org.apache.xerces.internal.impl.io.UTF8Reader;  import oracle.jdbc.oracore.TDSPatch;  public class Add extends HttpServlet {   // 驱动程序就是之前在classpath中配置的jdbc的驱动程序的jar包中    // 连接地址是由各个数据库生产商单独提供的，所以需要单独记住   public static final String DBURL = "jdbc:oracle:thin:@localhost:1521:LIUSY";   // 连接数据库的用户名   public static final String DBUSER = "scott";   // 连接数据库的密码   public static final String DBPASS = "tiger";    @Override   protected void doPost(HttpServletRequest req, HttpServletResponse resp)       throws ServletException, IOException   {     // TODO Auto-generated method stub     doGet(req, resp);   }    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException   {     //设置请求和响应的编码 ，不然页面上容易出现乱码     request.setCharacterEncoding("UTF-8");     response.setCharacterEncoding("UTF-8");         response.setContentType("text/html;UTF-8");     //输出流     PrintWriter out = response.getWriter();     //数据库连接代码     try     {       Connection conn = null; // 表示数据库的连接的对象       Statement pstmt = null; // 表示数据库的更新操作       String nameString=request.getParameter("name");       String grentString=request.getParameter("grent");       String resultString=request.getParameter("result");       System.out.print(nameString);       String sql="insert into student(id,name,calssGrent,result)

 values(perseq.nextval,'"+nameString+"','"+grentString+"','"+resultString+"')";          // 1、使用Class类加载驱动程序       Class.forName("oracle.jdbc.driver.OracleDriver");       // 2、连接数据库       conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);       pstmt=conn.createStatement();       int pd=pstmt.executeUpdate(sql);       if (pd!=0)       {         out.println("添加成功");         out.println("<br><a href=MMC_01>查看列表</a>");       }       conn.close();            }     catch (Exception e)     {       e.printStackTrace();     }     out.flush();     out.close();   }  }

web.xml 配置文件

<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5"    xmlns="http://java.sun.com/xml/ns/javaee"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  <display-name></display-name>   <welcome-file-list>   <welcome-file>index.jsp</welcome-file>  </welcome-file-list>   <servlet-name>MMC_01</servlet-name>   <servlet-class>org.lsy.servlet.MMC_01</servlet-class>  </servlet>  <servlet>   <servlet-name>delete</servlet-name>   <servlet-class>org.lsy.servlet.delete</servlet-class>  </servlet>  <servlet>   <servlet-name>Add</servlet-name>   <servlet-class>org.lsy.servlet.Add</servlet-class>  </servlet>  <servlet>   <servlet-name>AddPage</servlet-name>   <servlet-class>org.lsy.servlet.AddPage</servlet-class>  </servlet>  <servlet>   <servlet-name>UpdatePage</servlet-name>   <servlet-class>org.lsy.servlet.UpdatePage</servlet-class>  </servlet>  <servlet>   <servlet-name>Update</servlet-name>   <servlet-class>org.lsy.servlet.Update</servlet-class>  </servlet>    <servlet-mapping>   <servlet-name>MMC_01</servlet-name>   <url-pattern>/MMC_01</url-pattern>  </servlet-mapping>  <servlet-mapping>   <servlet-name>delete</servlet-name>   <url-pattern>/delete</url-pattern>  </servlet-mapping>  <servlet-mapping>   <servlet-name>Add</servlet-name>   <url-pattern>/Add</url-pattern>  </servlet-mapping>  <servlet-mapping>   <servlet-name>AddPage</servlet-name>   <url-pattern>/AddPage</url-pattern>  </servlet-mapping>  <servlet-mapping>   <servlet-name>UpdatePage</servlet-name>   <url-pattern>/UpdatePage</url-pattern>  </servlet-mapping>  <servlet-mapping>   <servlet-name>Update</servlet-name>   <url-pattern>/Update</url-pattern>  </servlet-mapping> </web-app>

本人并非老鸟，一直处于学习中，有什么错误的地方还请指证，上面的代码有很多重复的部分，很多不合理的地方，比较数据库连接直接暴露于操作servlet中，为了看的更直观，我就没有更改……

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。

上一篇：java 线程详解及线程与进程的区别

下一篇：Java int与integer的对比区别