Demo_JSP_JavaBean and demo_jsp_javabean for schema instances

Demo_JSP_JavaBean and demo_jsp_javabean for schema instances

Demo_JSP_JavaBean for schema instances

1,Development tools and development environment

Development tools: MyEclipse10, JDK1.6.0 _ 13 (32-bit), Tomcat7.0 (32-bit), and mysql5.7.13

Development Environment: WIN10

2,Demo_JSP_JavaBean implementation function

 User Logon, user registration, and logout.

3,Demo_JSP_Java_Bean Usage Technology

This example uses JSP, JavaBean, and JDBC to Implement User Logon, user registration, and logout. Figure 1 shows the system architecture:

 Figure 1: Demo_JSP_Java_Bean System Architecture

 

See figure 2 (logical relationship between JSP and JavaBean in the system ):

 

  

Figure 2: Logical Relationship Between JSP and JavaBean IN THE SYSTEM

 

4,Implementation

(1) create a new Web project in MyEclipse and name it Demo_JSP_JavaBean;

(2) Import mysql-connector-java-5.1.6-bin.jar to Demo_JSP project, this package is to achieve Java Connection database function package (will not import the package of students, can Baidu yo );

Attachment: mysql-connector-java-5.1.6-bin.jar, Baidu cloud download link: http://pan.baidu.com/s/1i5psdDF password: meyg

(3) create the following JavaBean file and JSP file in the Demo_JSP Project (PS: the JSP file code here is only part of the code, for other JSP file code, please refer to my previous blog Oh (link address: http://www.cnblogs.com/liuzhen1995/p/5700409.html )):

1) create a Java class DBAccess with the package name "liu" to implement the database login connection function. The specific code is as follows:

 

package liu;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class DBAccess {    private String drv = "com.mysql.jdbc.Driver";    private String url = "jdbc:mysql://localhost:3306/library_system";    private String usr = "root";    private String pwd = "root";    private Connection conn = null;    private Statement stm = null;    private ResultSet rs = null;    public boolean createConn() {        boolean b = false;        try {            Class.forName(drv).newInstance();            conn = DriverManager.getConnection(url, usr, pwd);            b = true;        } catch (SQLException e) {        } catch (ClassNotFoundException e) {        } catch (InstantiationException e) {        } catch (IllegalAccessException e) {        }        return b;    }    public boolean update(String sql) {        boolean b = false;        try {            stm = conn.createStatement();            stm.execute(sql);            b = true;        } catch (Exception e) {            System.out.println(e.toString());        }        return b;    }    public void query(String sql) {        try {            stm = conn.createStatement();            rs = stm.executeQuery(sql);        } catch (Exception e) {        }    }        public boolean next() {        boolean b = false;        try {            if(rs.next())b = true;        } catch (Exception e) {        }        return b;            }        public String getValue(String field) {        String value = null;        try {            if(rs!=null)value = rs.getString(field);        } catch (Exception e) {        }        return value;    }    public void closeConn() {        try {            if (conn != null)                conn.close();        } catch (SQLException e) {        }    }    public void closeStm() {        try {            if (stm != null)                stm.close();        } catch (SQLException e) {        }    }    public void closeRs() {        try {            if (rs != null)                rs.close();        } catch (SQLException e) {        }    }    public Connection getConn() {        return conn;    }    public void setConn(Connection conn) {        this.conn = conn;    }    public String getDrv() {        return drv;    }    public void setDrv(String drv) {        this.drv = drv;    }    public String getPwd() {        return pwd;    }    public void setPwd(String pwd) {        this.pwd = pwd;    }    public ResultSet getRs() {        return rs;    }    public void setRs(ResultSet rs) {        this.rs = rs;    }    public Statement getStm() {        return stm;    }    public void setStm(Statement stm) {        this.stm = stm;    }    public String getUrl() {        return url;    }    public void setUrl(String url) {        this.url = url;    }    public String getUsr() {        return usr;    }    public void setUsr(String usr) {        this.usr = usr;    }}

2) create a Java UserBean under the package created in the previous step to implement the database query and write functions. The Code is as follows:

package liu;public class UserBean {    public boolean valid(String username, String password) {        boolean isValid = false;        DBAccess db = new DBAccess();        if(db.createConn()) {            String sql = "select * from userInfo where username='"+username+"' and password='"+password+"'";            db.query(sql);            if(db.next()) {                isValid = true;            }            db.closeRs();            db.closeStm();            db.closeConn();        }        return isValid;    }        public boolean isExist(String username) {        boolean isExist = false;        DBAccess db = new DBAccess();        if(db.createConn()) {            String sql = "select * from userInfo where username='"+username+"'";            db.query(sql);            if(db.next()) {                isExist = true;            }            db.closeRs();            db.closeStm();            db.closeConn();        }        return isExist;    }        public void add(String username, String password, String email) {        DBAccess db = new DBAccess();        if(db.createConn()) {            String sql = "insert into userInfo(username,password,mail) values('"+username+"','"+password+"','"+email+"')";            db.update(sql);            db.closeStm();            db.closeConn();        }    }}

3) login_action.jsp: receives the username and password entered by the user on the login. jsp page and calls JavaBean for logon authentication. The specific code is as follows:

<%@ page import="liu.UserBean" %><%//get parametersString username = request.getParameter("username");String password = request.getParameter("password");//check nullif (username == null || password == null) {    response.sendRedirect("login.jsp");}//validateUserBean userBean = new UserBean();boolean isValid = userBean.valid(username, password);if (isValid) {    session.setAttribute("username", username);    response.sendRedirect("welcome.jsp");} else {    response.sendRedirect("login.jsp");}%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

4) register_action.jsp: registers data by calling JavaBean and writes data to the database. The specific code is as follows:

<%@ page import="liu.UserBean" %><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%//get parametersString username = request.getParameter("username");String password1 = request.getParameter("password1");String password2 = request.getParameter("password2");String email = request.getParameter("email");//check nullif (username == null || password1 == null || password2 == null || !password1.equals(password2)) {    response.sendRedirect("register.jsp");}//validateUserBean userBean = new UserBean();boolean isExist = userBean.isExist(username);if(!isExist) {    userBean.add(username, password1, email);    response.sendRedirect("login.jsp");} else {    response.sendRedirect("register.jsp");}%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

5,Running result display

For specific running results, please refer to my previous blog Oh, running results are exactly the same (link address: http://www.cnblogs.com/liuzhen1995/p/5700409.html )~~~

Appendix: Demo_JSP_JavaBean project source code file Baidu cloud download link: http://pan.baidu.com/s/1sl1nd9r password: lrdk; this instance uses the database to Create Table SQL statement File Download link: http://pan.baidu.com/s/1eS0n9aM password: 7ttd