Servlet+JSP实现简单的员工CRUD(附源码)

Servlet+JSP实现简单的员工CRUD(附源码)

源码链接

链接：https://pan.baidu.com/s/1spZBEvrrWp4SwuQrR2WVwg 密码：65i7

环境搭建

JDK1.8以上
Tomcat 9
Mysql
Eclipse

运行效果截图

由于我们的重点放在Java后端，所以页面简陋点，能看就行

前言

这里我们只设计一张数据表，项目虽然简单，但对Servlet+JSP和MVC设计模式有深刻的认识。在练习完该项目后，我还为大家准备了该项目的SpringMVC+Mybatis的实现版，SpringMVC+MyBatis是目前最流行的框架

项目结构

这里我用的是Maven构建的项目结构，大家也可以直接新建动态web项目。

数据表

CREATE TABLE emp (
id int(10) NOT NULL AUTO_INCREMENT,
name varchar(255) DEFAULT NULL,
salary double DEFAULT NULL,
age int(10) DEFAULT NULL,
PRIMARY KEY (id)
)

实体类

   public class EmpEntity {
    private int id;
    private String name;
    private double salary;
    private int age;
    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 double getSalary() {
        return salary;
    }
    public void setSalary(double salary) {
        this.salary = salary;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

DBUtil类

public class DBUtil {

//设置数据库和连接池变量
final String driver = "com.mysql.jdbc.Driver";
final String url = "jdbc:mysql://localhost:3306/emp?useUnicode=true&characterEncoding=utf8&useSSL=false" ;
final String user = "root" ;
final String password = "" ;

/**
 * 专门负责加载数据库驱动的方法
 */
public void load() {
    try {
        Class.forName( driver ) ;
        System.out.println( "数据库驱动[ " + driver + "] 加载成功." );
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
        System.out.println( "数据库驱动[ " + driver + "] 加载失败" );
    }
}

/**
 * 专门负责获得数据库连接的方法
 * @return
 */
public Connection getConnection() {

    load();

    Connection conn = null ;

    try {
        conn = DriverManager.getConnection(url, user, password);
        return conn ; 
    } catch (SQLException e) {
        throw new RuntimeException( "连接数据库失败" , e );
    }

}
//关闭连接
public void closeConnection(Connection con,PreparedStatement ps,ResultSet rs) throws SQLException{
    if(rs!=null){
        rs.close();
    }
    if(ps!=null){
        ps.close();
    }
    if(con!=null){
        con.close();
    }
}

}

EmpDao类

public class EmpDao {
DBUtil dbu=new DBUtil();
// 查找所有员工
public List<Emp> findAll() {
    List<Emp> empList = new ArrayList<Emp>();
    Connection con = null;
    PreparedStatement ps = null;
    ResultSet rs = null;
    try {
        con = dbu.getConnection();
        String sql = "SELECT id,name,salary,age FROM emp";
        ps = con.prepareStatement(sql);
        rs = ps.executeQuery();
        while (rs.next()) {
            Emp emp = new Emp();
            emp.setId(rs.getInt("id"));
            emp.setName(rs.getString("name"));
            emp.setSalary(rs.getDouble("salary"));
            emp.setAge(rs.getInt("age"));
            empList.add(emp);
        }
    } catch (SQLException e) {
        e.printStackTrace();
        ;
    } finally {
        try {
            dbu.closeConnection(con, ps, rs);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    return empList;
}

public void addEmp(Emp emp){
    Connection con=null;
    PreparedStatement ps=null;
    String sql="INSERT INTO emp(name,salary,age) values(?,?,?)";
    try {

        con = dbu.getConnection();
        ps=con.prepareStatement(sql);
        ps.setString(1, emp.getName());
        ps.setDouble(2, emp.getSalary());
        ps.setInt(3, emp.getAge());
        int flag=ps.executeUpdate();
        if(flag>0) {
            System.out.println("添加员工成功！");
        }

    }catch(SQLException e) {
        e.printStackTrace();
    }finally {
        try {
            dbu.closeConnection(con, ps, null);
        }catch(SQLException e) {
            e.printStackTrace();
        }
    }       
}
public void deleteEmp(int id) {
    Connection con=null;
    PreparedStatement ps=null;
    String sql="DELETE FROM emp WHERE id=?";
    try {
        con=dbu.getConnection();
        ps=con.prepareStatement(sql);
        ps.setInt(1, id);
        int flag=ps.executeUpdate();
        if(flag>0) {
            System.out.println("删除员工成功！");
        }
    }catch(SQLException e) {
        e.printStackTrace();
    }finally {
        try {
            dbu.closeConnection(con, ps, null);
        }catch(SQLException e) {
            e.printStackTrace();
        }
    }
}
public Emp loadEmp(int id){
    Emp emp = null;
    Connection con=null;
    PreparedStatement ps=null;
    ResultSet rs=null;
    try {
        con=dbu.getConnection();
        String sql="select * from emp where id =?";
        ps=con.prepareStatement(sql);
        ps.setInt(1, id);
        rs=ps.executeQuery();
        while(rs.next()){
            emp=new Emp();
            emp.setId(rs.getInt("id"));
            emp.setName(rs.getString("name"));
            emp.setSalary(rs.getDouble("salary"));
            emp.setAge(rs.getInt("age"));
        }
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }finally{
        try {
            dbu.closeConnection(con, ps, null);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    return emp;
}   

public void updateEmp(Emp emp) {
    Connection con=null;
    PreparedStatement ps=null;
    String sql="UPDATE emp SET name=?,salary=?,age=? where id=?";
    try {
        con=dbu.getConnection();
        ps=con.prepareStatement(sql);
        ps.setString(1, emp.getName());
        ps.setDouble(2, emp.getSalary());
        ps.setInt(3, emp.getAge());
        ps.setInt(4, emp.getId());
        int flag=ps.executeUpdate();
        if(flag>0) {
            System.out.println("更新成功！");
        }
    }catch(SQLException e) {
        e.printStackTrace();
    }finally {
        try {
            dbu.closeConnection(con, ps, null);
        }catch(SQLException e) {
            e.printStackTrace();
        }
    }
}

}

EmpServlet类

public class EmpServlet extends HttpServlet {
private EmpDao empDao = new EmpDao();
private static final long serialVersionUID = 1L;

public EmpServlet() {
    super();
}

protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    doPost(request, response);

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    request.setCharacterEncoding("utf-8");
    response.setContentType("text/html;charset=utf-8");
    String url = request.getRequestURI();
    String action = request.getRequestURI().substring(url.lastIndexOf('/') + 1, url.lastIndexOf('.'));
    if ("list".equals(action)) {
        List<Emp> listEmp = empDao.findAll();
        request.setAttribute("listEmp", listEmp);
        request.getRequestDispatcher("listEmp.jsp").forward(request, response);
    } else if ("add".equals(action)) {
        Emp emp = new Emp();
        emp.setName(request.getParameter("name"));
        emp.setSalary(Double.parseDouble(request.getParameter("salary")));
        emp.setAge(Integer.parseInt(request.getParameter("age")));
        empDao.addEmp(emp);
        response.sendRedirect("list.do");
    } else if ("delete".equals(action)) {
        int id = Integer.parseInt(request.getParameter("id"));
        empDao.deleteEmp(id);
        response.sendRedirect("list.do");
    } else if ("load".equals(action)) {
        Emp emp = empDao.loadEmp(Integer.parseInt(request.getParameter("id")));
        request.setAttribute("emp", emp);
        request.getRequestDispatcher("empInfo.jsp").forward(request, response);
    } else if ("update".equals(action)) {
        Emp emp = new Emp();
        emp.setId(Integer.parseInt(request.getParameter("id")));
        emp.setName(request.getParameter("name"));
        emp.setSalary(Double.parseDouble(request.getParameter("salary")));
        emp.setAge(Integer.parseInt(request.getParameter("age")));
        empDao.updateEmp(emp);
        response.sendRedirect("list.do");
    }

}

}

前台页面

这里就不复制过来了，直接参照源码
链接：https://pan.baidu.com/s/1spZBEvrrWp4SwuQrR2WVwg 密码：65i7