html调用servlet（JDBC在Servlet中的使用）（1）
1.页面的数据表单
在使用Servlet处理用户请求之前，先准备一个页面，该页面用来提供数据表单。数据表单就是HTML中的...部分，当用户单击Submit按钮提交表单之后，表单中包含的一些变量（或者成为字段）将会被发送到服务器端进行处理。下面编写一个HTML文件，文件代码如下：
add.html
add.html-->请输入部门信息：
部门号：
部门名：
部门人数：
地址：
2.添加数据
Servlet的好处之一就是可以简单地获得表单中的数据。在Servlet中使用JDBC技术实现添加的代码如下：
addServlet.java
packagecom.cn.add;importjava.io.IOException;importjava.io.PrintWriter;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.PreparedStatement;importjava.sql.SQLException;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;publicclassaddServletextendsHttpServlet {/*** Constructor of the object.*/publicaddServlet() {super();
}/*** Destruction of the servlet.
*/publicvoiddestroy() {super.destroy();//Just puts "destroy" string in log//Put your code here}/*** The doGet method of the servlet.
*
* This method is called when a form has its tag value method equals to get.
*
*@paramrequest the request send by the client to the server
*@paramresponse the response send by the server to the client
*@throwsServletException if an error occurred
*@throwsIOException if an error occurred*/publicvoiddoGet(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {
response.setContentType("text/html;charset=gb2312");
PrintWriter out=response.getWriter();this.doPost(request, response);
out.flush();
out.close();
}/*** The doPost method of the servlet.
*
* This method is called when a form has its tag value method equals to post.
*
*@paramrequest the request send by the client to the server
*@paramresponse the response send by the server to the client
*@throwsServletException if an error occurred
*@throwsIOException if an error occurred*/publicvoiddoPost(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {
System.out.println("到了Servlet！！！");
response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out=response.getWriter();
String id= request.getParameter("id");//获取部门编号String name = request.getParameter("name");//获取部门名称String address = request.getParameter("address");//获取部门所在地址intnum = Integer.parseInt(request.getParameter("num"));//获取部门人数Connection conn =null;//声明一个Connection对象，用来连接数据库PreparedStatement pstmt =null;//声明PreparedStatement对象，用来向数据库插入数据条数据try{//连接到MySQL数据库中的bank数据库模式Class.forName("com.mysql.jdbc.Driver");
System.out.println("创建驱动成功！");//连接数据库conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
System.out.println("连接数据库成功！");//插入数据的SQL语句String sql = "INSERT INTO dept(id,d_name,address,empnumber) VALUES(?,?,?,?)";
pstmt=conn.prepareStatement(sql);//设置插入数据的顺序pstmt.setString(1, id);
pstmt.setString(2, name);
pstmt.setString(3, address);
pstmt.setInt(4, num);intresult =pstmt.executeUpdate();//判断执行结果if(result == 1) {
out.print("插入数据成功！");
}else{
out.print("插入数据失败！请重新插入！");
}
}catch(ClassNotFoundException e) {//TODO Auto-generated catch blocke.printStackTrace();
}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();
}
out.flush();
out.close();
}/*** Initialization of the servlet.
*
*@throwsServletException if an error occurs*/publicvoidinit()throwsServletException {//Put your code here}
}
web.xml
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">This is the description of my J2EE componentThis is the display name of my J2EE componentaddServletcom.cn.add.addServletaddServlet/servlet/addServletindex.jsp
文件整体框架如下：
3.查看单条数据
一般一条数据的id是唯一的，查看单条记录的时候，可以根据id来查询。HTML页面的代码如下：
showById.html
showById.html-->请输入部门编号：
在该页面中输如id号，点击查找按钮时会进入查询的Servlet，在Servlet中处理根据id查询的操作。根据id查询的Servlet代码如下：
SearchEmployee.java
packagecom.cn.query;importjava.io.IOException;importjava.io.PrintWriter;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.PreparedStatement;importjava.sql.ResultSet;importjava.sql.SQLException;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;publicclassSearchEmployeeextendsHttpServlet {/*** Destruction of the servlet.
*/publicvoiddestroy() {super.destroy();//Just puts "destroy" string in log//Put your code here}/*** The doGet method of the servlet.
*
* This method is called when a form has its tag value method equals to get.
*
*@paramrequest the request send by the client to the server
*@paramresponse the response send by the server to the client
*@throwsServletException if an error occurred
*@throwsIOException if an error occurred*/publicvoiddoGet(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {
response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out=response.getWriter();
String id= request.getParameter("id");//获取部门编号Connection conn =null;//声明一个Connection对象，用来连接数据库PreparedStatement pstmt =null;
ResultSet rs=null;try{
Class.forName("com.mysql.jdbc.Driver");
System.out.println("创建驱动成功！");//连接数据库conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
System.out.println("连接数据库成功！");
String sql= "SELECT * FROM dept WHERE id = ?";
pstmt=conn.prepareStatement(sql);
pstmt.setString(1, id);
rs=pstmt.executeQuery();
}catch(ClassNotFoundException e) {//TODO Auto-generated catch blocke.printStackTrace();
}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();
}try{while(rs.next()){
out.print("部门编号："+rs.getString(1)+"\n");
out.print("部门名称："+rs.getString(2)+"\n");
out.print("部门地址："+rs.getString(3)+"\n");
out.print("部门人数："+rs.getString(4)+"\n");
}
}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();
}
out.flush();
out.close();
}/*** The doPost method of the servlet.
*
* This method is called when a form has its tag value method equals to post.
*
*@paramrequest the request send by the client to the server
*@paramresponse the response send by the server to the client
*@throwsServletException if an error occurred
*@throwsIOException if an error occurred*/publicvoiddoPost(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {
response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out=response.getWriter();this.doGet(request, response);
out.flush();
out.close();
}/*** Initialization of the servlet.
*
*@throwsServletException if an error occurs*/publicvoidinit()throwsServletException {//Put your code here}
}
目录结构如下：
4.显示一张表中的全部数据
显示表中全部数据信息的Servlet代码如下：
DeptList.java
packagecom.cn.query;importjava.io.IOException;importjava.io.PrintWriter;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.ResultSet;importjava.sql.SQLException;importjava.sql.Statement;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;publicclassDeptListextendsHttpServlet {/*** The doGet method of the servlet.
*
* This method is called when a form has its tag value method equals to get.
*
*@paramrequest the request send by the client to the server
*@paramresponse the response send by the server to the client
*@throwsServletException if an error occurred
*@throwsIOException if an error occurred*/publicvoiddoGet(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {
response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out=response.getWriter();
Connection conn=null;
Statement stmt=null;
ResultSet rs=null;try{
Class.forName("com.mysql.jdbc.Driver");
conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
stmt=conn.createStatement();
rs= stmt.executeQuery("SELECT * FROM dept");//在页面中显示表中的所有信息out.println(""+ "部门表信息"+ "");
out.println("
部门表信息:
");//循环遍历输出查询结果while(rs.next()){
out.print("部门编号：");
out.print(rs.getString(1)+"\t");
out.print("部门名称：");
out.print(rs.getString(2)+"\t");
out.print("部门地址：");
out.print(rs.getString(3)+"\t");
out.print("部门人数：");
out.print(rs.getString(4)+"\t");
out.print("
");
}
out.print("");
out.close();
}catch(ClassNotFoundException e) {//TODO Auto-generated catch blocke.printStackTrace();
}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();
}
}publicvoidinit()throwsServletException {//Put your code here}
}
