CRUD In Servlet

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A crud application is the most important application for any project growth. We can easily create a Crud Application in Servlet.

Servlet Crud Example

Create a “user905” table in the oracle database with auto incrementing id using sequence. Id, name, password, email and country are the five fields in the table.

File:index.html

DOCTYPE html>  
<html>  
<head>  
<meta charset="ISO-8859-1">  
<title>Insert title here</title>  
</head>  
<body>    

<h1>Add New Employee</h1>  
<form action="SaveServlet" method="post">  
<table>  
<tr><td>Name:</td><td><input type="text" name="name"/></td></tr>  
<tr><td>Password:</td><td><input type="password" name="password"/></td></tr>  
<tr><td>Email:</td><td><input type="email" name="email"/></td></tr>  
<tr><td>Country:</td><td>  
<select name="country" style="width:150px">  
<option>India</option>  
<option>USA</option>  
<option>UK</option>  
<option>Other</option>  
</select>  
</td></tr>  
<tr><td colspan="2"><input type="submit" value="Save Employee"/></td></tr>  
</table>  
</form>   

<br/>  
<a href="ViewServlet">view employees</a>   

</body>  
</html>

File:Emp.java

public class Emp {  
private int id;  
private String name,password,email,country;  
public int getId() {  
    return id;  
}  
public void setId(int id) {  
    this.id = id;  
}  
public String getName() {  
    return name;  
}  
public void setName(String name) {  
    this.name = name;  
}  
public String getPassword() {  
    return password;  
}  
public void setPassword(String password) {  
    this.password = password;  
}  
public String getEmail() {  
    return email;  
}  
public void setEmail(String email) {  
    this.email = email;  
}  
public String getCountry() {  
    return country;  
}  
public void setCountry(String country) {  
    this.country = country;  
}    

}

File:EmpDao.java

import java.util.*;  
import java.sql.*;   

public class EmpDao {    

    public static Connection getConnection(){  
        Connection con=null;  
        try{  
            Class.forName("oracle.jdbc.driver.OracleDriver");  
            con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","system","oracle");  
        }catch(Exception e){System.out.println(e);}  
        return con;  
    }  
    public static int save(Emp e){  
        int status=0;  
        try{  
            Connection con=EmpDao.getConnection();  
            PreparedStatement ps=con.prepareStatement(  
                         "insert into user905(name,password,email,country) values (?,?,?,?)");  
            ps.setString(1,e.getName());  
            ps.setString(2,e.getPassword());  
            ps.setString(3,e.getEmail());  
            ps.setString(4,e.getCountry());               

            status=ps.executeUpdate();               

            con.close();  
        }catch(Exception ex){ex.printStackTrace();}  
          
        return status;  
    }  
    public static int update(Emp e){  
        int status=0;  
        try{  
            Connection con=EmpDao.getConnection();  
            PreparedStatement ps=con.prepareStatement(  
                         "update user905 set name=?,password=?,email=?,country=? where id=?");  
            ps.setString(1,e.getName());  
            ps.setString(2,e.getPassword());  
            ps.setString(3,e.getEmail());  
            ps.setString(4,e.getCountry());  
            ps.setInt(5,e.getId());  
              
            status=ps.executeUpdate();               

            con.close();  
        }catch(Exception ex){ex.printStackTrace();}  
          
        return status;  
    }  
    public static int delete(int id){  
        int status=0;  
        try{  
           Connection con=EmpDao.getConnection();  
            PreparedStatement ps=con.prepareStatement("delete from user905 where id=?");  
            ps.setInt(1,id);  
            status=ps.executeUpdate();               

            con.close();  
        }catch(Exception e){e.printStackTrace();}  
          
        return status;  
    }  
    public static Emp getEmployeeById(int id){  
        Emp e=new Emp();  
       
        try{  
            Connection con=EmpDao.getConnection();  
            PreparedStatement ps=con.prepareStatement("select * from user905 where id=?");  
            ps.setInt(1,id);  
            ResultSet rs=ps.executeQuery();  
            if(rs.next()){  
                e.setId(rs.getInt(1));  
                e.setName(rs.getString(2));  
                e.setPassword(rs.getString(3));  
                e.setEmail(rs.getString(4));  
                e.setCountry(rs.getString(5));  
            }  
            con.close();  
        }catch(Exception ex){ex.printStackTrace();}  
          
        return e;  
    }  
    public static List<Emp> getAllEmployees(){  
       List<Emp> list=new ArrayList<Emp>();            

        try{  
            Connection con=EmpDao.getConnection();  
            PreparedStatement ps=con.prepareStatement("select * from user905");  
            ResultSet rs=ps.executeQuery();  
            while(rs.next()){  
                Emp e=new Emp();  
                e.setId(rs.getInt(1));  
                e.setName(rs.getString(2));  
                e.setPassword(rs.getString(3));  
                e.setEmail(rs.getString(4));  
                e.setCountry(rs.getString(5));  
                list.add(e);  
            }  
            con.close();  
        }catch(Exception e){e.printStackTrace();}  
          
        return list;  
    }  
}

File:SaveServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  

import javax.servlet.ServletException;  
import javax.servlet.annotation.WebServlet;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
@WebServlet("/SaveServlet")  
public class SaveServlet extends HttpServlet {  
    protected void doPost(HttpServletRequest request, HttpServletResponse response)   
         throws ServletException, IOException {  
        response.setContentType("text/html");  
        PrintWriter out=response.getWriter();           

        String name=request.getParameter("name");  
        String password=request.getParameter("password");  
        String email=request.getParameter("email");  
        String country=request.getParameter("country");           

        Emp e=new Emp();  
        e.setName(name);  
        e.setPassword(password);  
        e.setEmail(email);  
        e.setCountry(country);            

        int status=EmpDao.save(e);  
        if(status>0){  
            out.print("

Record saved successfully!

");  
            request.getRequestDispatcher("index.html").include(request, response);  
        }else{  
            out.println("Sorry! unable to save record");  
        }            

        out.close();  
    }  
  
}

File:EditServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  
  
import javax.servlet.ServletException;  
import javax.servlet.annotation.WebServlet;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
@WebServlet("/EditServlet")  
public class EditServlet extends HttpServlet {  
    protected void doGet(HttpServletRequest request, HttpServletResponse response)   
           throws ServletException, IOException {  
        response.setContentType("text/html");  
        PrintWriter out=response.getWriter();  
        out.println("

Update Employee

");  
        String sid=request.getParameter("id");  
        int id=Integer.parseInt(sid);  
          
        Emp e=EmpDao.getEmployeeById(id);  
          
        out.print("

);  
        out.print("

);  
        out.print("
");  
        out.print("Name:");  
        out.print("Password:/>  
                </td></tr>");  
        out.print("Email:");  
        out.print("Country:");  
        out.print(");  
        out.print("India");  
        out.print("USA");  
        out.print("UK");  
        out.print("Other"

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CRUD In Servlet

Contents

Servlet Crud Example

Update Employee