JDBC连接数据库Servlet+Jsp实现增删改查

deme的结构图，采用的是三层架构，降低耦合度。

public class DBHelper {
	//属性，必须为私有变量
	private Connection conn;
	private Statement state;
	private PreparedStatement prep;
	
	//构造方法
	public DBHelper(){
		try {
			Class.forName("com.mysql.jdbc.Driver");
			conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/demo","root","root");
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	//方法
		//增删改
		public int update(String sql) throws SQLException{
			state=conn.createStatement();
			int temp=prep.executeUpdate(sql);  //增删改最后要返回一个整形变量
	  	return  temp;
		}
		//方法重载，当所变化的变量个数不确定的时候，就要用到表达式
		public int update(String sql,Object ... arr) throws SQLException{
			prep=conn.prepareStatement(sql);
			//给问号赋值
			for(int i=0;i

	public static void main(String[] args) {
		System.out.println(getConnection());
	}

测试一下，是否连接成功

连接成功

接下来创建实体类Employee

import java.io.Serializable;

public class Employee implements Serializable{

    /**
     *
     */
    private static final long serialVersionUID = 1L;
    //   ps:写属性推荐一个冷门的快捷键 shift+alt+a  谁用谁知道
    private int employeeId;
    private String employeeName;
    private String employeeSex;
    private String employeePhone;
    private String employeeEmail;

    // shift+alt+s   选择Generate Getters and setters to create  生成get set方法
    public int getEmployeeId() {
        return employeeId;
    }
    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }
    public String getEmployeeName() {
        return employeeName;
    }
    public void setEmployeeName(String employeeName) {
        this.employeeName = employeeName;
    }
    public String getEmployeeSex() {
        return employeeSex;
    }
    public void setEmployeeSex(String employeeSex) {
        this.employeeSex = employeeSex;
    }
    public String getEmployeePhone() {
        return employeePhone;
    }
    public void setEmployeePhone(String employeePhone) {
        this.employeePhone = employeePhone;
    }
    public String getEmployeeEmail() {
        return employeeEmail;
    }
    public void setEmployeeEmail(String employeeEmail) {
        this.employeeEmail = employeeEmail;
    }
}

查询列表

DAO里写方法

public List getAllEmployee(){
    List list = new ArrayList();
    Connection conn = DBHelper.getConnection();
    String sql  = "select * from Employee";
    try {
        PreparedStatement pst = conn.prepareStatement(sql);
        ResultSet rst = pst.executeQuery();
        while (rst.next()) {
            Employee employee = new Employee();
            employee.setEmployeeEmail(rst.getString("EmployeeEmail"));
            employee.setEmployeeId(rst.getInt("EmployeeId"));
            employee.setEmployeeName(rst.getString("EmployeeName"));
            employee.setEmployeePhone(rst.getString("EmployeePhone"));
            employee.setEmployeeSex(rst.getString("EmployeeSex"));
            list.add(employee);
        }
        rst.close();
        pst.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return list;
}

自动创建一个servlet类，或者继承HttpServlet类。

public class EmployeeShowServlet  extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        EmployeeDao dao = new EmployeeDao();
        List list = dao.getAllEmployee();
        req.setAttribute("list", list);
        req.getRequestDispatcher("index.jsp").forward(req, resp);
    }


}

最后在xml文件里面配置写好的servlet

<servlet>
    <servlet-name>employeeShowServletservlet-name>
    <servlet-class>com.xgyb.servlet.EmployeeShowServletservlet-class>
servlet>
<servlet-mapping>
    <servlet-name>employeeShowServletservlet-name>
    <url-pattern>/employeeShowServleturl-pattern>
servlet-mapping>

jsp页面

<table>
    <tr>
        <td>编号td>
        <td>姓名td>
        <td>性别td>
        <td>电话td>
        <td>邮箱td>
        <td>操作td>
    tr>
    <c:forEach items="${list}" var="item">
        <tr>
            <td>${item.employeeId }td>
            <td>${item.employeeName }td>
            <td>${item.employeeSex }td>
            <td>${item.employeePhone }td>
            <td>${item.employeeEmail }td>
        tr>
    c:forEach>
   table>

启动tomcat      在浏览器输入：http://localhost:8080/EmployeeManager/employeeShowServlet

实现添加

dao层

public boolean addEmployee(Employee employee){
        String sql = "INSERT INTO `employee`(`EmployeeName`,`EmployeeSex`,`EmployeePhone`,`EmployeeEmail`) VALUES (?,?,?,?)";
        Connection conn = DBHelper.getConnection();
        try {
            PreparedStatement pst = conn.prepareStatement(sql);
            pst.setString(1, employee.getEmployeeName());
            pst.setString(2, employee.getEmployeeSex());
            pst.setString(3, employee.getEmployeePhone());
            pst.setString(4, employee.getEmployeeEmail());
            int count = pst.executeUpdate();
            pst.close();
            return count>0?true:false;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }

创建EmployeeAddServlet

public class EmployeeAddServlet extends HttpServlet{
    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String employeeName = req.getParameter("employeeName");
        String employeeSex = req.getParameter("employeeSex");
        String employeePhone = req.getParameter("employeePhone");
        String employeeEmail = req.getParameter("employeeEmail");
        Employee employee = new Employee();
        employee.setEmployeeEmail(employeeEmail);
        employee.setEmployeeName(new String(employeeName.getBytes("ISO-8859-1"),"UTF-8"));
        employee.setEmployeePhone(employeePhone);
        employee.setEmployeeSex(new String(employeeSex.getBytes("ISO-8859-1"),"UTF-8"));
        EmployeeDao dao = new EmployeeDao();
        dao.addEmployee(employee);
        req.getRequestDispatcher("employeeShowServlet").forward(req, resp);
    }
}

xml配置

<servlet>
    <servlet-name>employeeAddServletservlet-name>
    <servlet-class>com.xgyb.servlet.EmployeeAddServletservlet-class>
servlet>
<servlet-mapping>
    <servlet-name>employeeAddServletservlet-name>
    <url-pattern>/employeeAddServleturl-pattern>
servlet-mapping>

jsp

<form action="employeeAddServlet" method="post">
  <table border="1">
    <tr>
        <td colspan="2"><h1>添加员工h1>td>
    tr>
    <tr>
        <td>姓名:td>
        <td><input  type="text" name="employeeName"/>td>
    tr>
    <tr>
        <td>性别:td>
        <td><input  type="text" name="employeeSex"/>td>
    tr>
    <tr>
        <td>电话:td>
        <td><input  type="text" name="employeePhone"/>td>
    tr>
    <tr>
        <td>邮箱:td>
        <td><input  type="text" name="employeeEmail"/>td>
    tr>
    <tr>
        <td colspan="2"><input  type="submit" value="提交"/>td>
    tr>
  table>
 form>

输入：http://localhost:8080/EmployeeManager/addEmployee.jsp

添加成功                                        

Dao  修改有两个，根据id选中需要修改的内容

public boolean updateEmployee(Employee employee){
        String sql = "UPDATE `employee` SET `EmployeeName`=?,`EmployeeSex`=?,`EmployeePhone`=?,`EmployeeEmail`=? WHERE `EmployeeId` = ?";
        Connection conn = DBHelper.getConnection();
        try {
            PreparedStatement pst = conn.prepareStatement(sql);
            pst.setString(1, employee.getEmployeeName());
            pst.setString(2, employee.getEmployeeSex());
            pst.setString(3, employee.getEmployeePhone());
            pst.setString(4, employee.getEmployeeEmail());
            pst.setInt(5, employee.getEmployeeId());
            int count = pst.executeUpdate();
            pst.close();
            return count>0?true:false;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }

public Employee selectEmployeeById(int id){
        Connection conn = DBHelper.getConnection();
        String sql  = "select * from Employee where EmployeeId = "+id;
        Employee employee = null;
        try {
            PreparedStatement pst = conn.prepareStatement(sql);
            ResultSet rst = pst.executeQuery();
            while (rst.next()) {
                employee = new Employee();
                employee.setEmployeeEmail(rst.getString("EmployeeEmail"));
                employee.setEmployeeId(rst.getInt("EmployeeId"));
                employee.setEmployeeName(rst.getString("EmployeeName"));
                employee.setEmployeePhone(rst.getString("EmployeePhone"));
                employee.setEmployeeSex(rst.getString("EmployeeSex"));
            }
            rst.close();
            pst.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return employee;
    }

Servlet

public class EmployeeupdateServlet extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String idStr = req.getParameter("id");
        if(idStr != null && !idStr.equals("")){
            int id = Integer.valueOf(idStr);
            EmployeeDao dao = new EmployeeDao();
            Employee employee = dao.selectEmployeeById(id);
            req.setAttribute("employee", employee);
        }
        req.getRequestDispatcher("updateEmployee.jsp").forward(req, resp);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String employeeName = req.getParameter("employeeName");
        String employeeSex = req.getParameter("employeeSex");
        String employeePhone = req.getParameter("employeePhone");
        String employeeEmail = req.getParameter("employeeEmail");
        String idStr = req.getParameter("employeeId");
        Employee employee = new Employee();
        employee.setEmployeeId(Integer.valueOf(idStr));
        employee.setEmployeeEmail(employeeEmail);
        employee.setEmployeeName(new String(employeeName.getBytes("ISO-8859-1"),"UTF-8"));
        employee.setEmployeePhone(employeePhone);
        employee.setEmployeeSex(new String(employeeSex.getBytes("ISO-8859-1"),"UTF-8"));
        EmployeeDao dao = new EmployeeDao();
        dao.updateEmployee(employee);
        req.getRequestDispatcher("employeeShowServlet").forward(req, resp);
    }
}

跟前篇一样需要在xml 配置一下，这个很简单自己试着写。

修改用的页面就是增加的页面。

至尊宝  改成了孙悟空。

Dao  修改有两个，根据id选中需要修改的内容

public boolean updateEmployee(Employee employee){
        String sql = "UPDATE `employee` SET `EmployeeName`=?,`EmployeeSex`=?,`EmployeePhone`=?,`EmployeeEmail`=? WHERE `EmployeeId` = ?";
        Connection conn = DBHelper.getConnection();
        try {
            PreparedStatement pst = conn.prepareStatement(sql);
            pst.setString(1, employee.getEmployeeName());
            pst.setString(2, employee.getEmployeeSex());
            pst.setString(3, employee.getEmployeePhone());
            pst.setString(4, employee.getEmployeeEmail());
            pst.setInt(5, employee.getEmployeeId());
            int count = pst.executeUpdate();
            pst.close();
            return count>0?true:false;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }

public Employee selectEmployeeById(int id){
        Connection conn = DBHelper.getConnection();
        String sql  = "select * from Employee where EmployeeId = "+id;
        Employee employee = null;
        try {
            PreparedStatement pst = conn.prepareStatement(sql);
            ResultSet rst = pst.executeQuery();
            while (rst.next()) {
                employee = new Employee();
                employee.setEmployeeEmail(rst.getString("EmployeeEmail"));
                employee.setEmployeeId(rst.getInt("EmployeeId"));
                employee.setEmployeeName(rst.getString("EmployeeName"));
                employee.setEmployeePhone(rst.getString("EmployeePhone"));
                employee.setEmployeeSex(rst.getString("EmployeeSex"));
            }
            rst.close();
            pst.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return employee;
    }

Servlet

public class EmployeeupdateServlet extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String idStr = req.getParameter("id");
        if(idStr != null && !idStr.equals("")){
            int id = Integer.valueOf(idStr);
            EmployeeDao dao = new EmployeeDao();
            Employee employee = dao.selectEmployeeById(id);
            req.setAttribute("employee", employee);
        }
        req.getRequestDispatcher("updateEmployee.jsp").forward(req, resp);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String employeeName = req.getParameter("employeeName");
        String employeeSex = req.getParameter("employeeSex");
        String employeePhone = req.getParameter("employeePhone");
        String employeeEmail = req.getParameter("employeeEmail");
        String idStr = req.getParameter("employeeId");
        Employee employee = new Employee();
        employee.setEmployeeId(Integer.valueOf(idStr));
        employee.setEmployeeEmail(employeeEmail);
        employee.setEmployeeName(new String(employeeName.getBytes("ISO-8859-1"),"UTF-8"));
        employee.setEmployeePhone(employeePhone);
        employee.setEmployeeSex(new String(employeeSex.getBytes("ISO-8859-1"),"UTF-8"));
        EmployeeDao dao = new EmployeeDao();
        dao.updateEmployee(employee);
        req.getRequestDispatcher("employeeShowServlet").forward(req, resp);
    }
}

跟前篇一样需要在xml 配置一下，这个很简单自己试着写。

修改用的页面就是增加的页面。

至尊宝  改成了孙悟空。

删除就非常简单了，根据id来删除人物。

public boolean deleteEmployee(int id){
        String sql = "delete from Employee where EmployeeId = ?";
        Connection conn = DBHelper.getConnection();
        try {
            PreparedStatement pst = conn.prepareStatement(sql);
            pst.setInt(1, id);
            int count = pst.executeUpdate();
            pst.close();
            return count>0?true:false;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }

servlet

public class EmployeeDeleteServlet extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String idStr = req.getParameter("id");
        if(idStr != null && !idStr.equals("")){
            int id = Integer.valueOf(idStr);
            EmployeeDao dao = new EmployeeDao();
            dao.deleteEmployee(id);
        }
        req.getRequestDispatcher("employeeShowServlet").forward(req, resp);
    }
}

别忘了配置xml文件

牛魔王被删掉了，是不是很简单。

http://download.csdn.net/download/alexander_yun/10129982       

项目的代码，建议手动敲完