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Depuis trois jours, j'essaie de développer une application CRUD basée sur le web qui fait toutes les opérations CRUD. Compte tenu de la complexité du code, j'ai décidé de montrer d'abord les données puis de passer à d'autres opérations CRUD.Comment afficher des données dans une page Web à partir de la base de données?
Pour cette application, j'ai posté plusieurs questions ici. D'après les réponses, je suis venu aussi loin.
Voici mon code source complet. Il ne montre aucune erreur. Mais je ne suis pas capable d'obtenir la sortie.
J'ai deux classes dans mon code côté serveur. Pour moi, ça a l'air bien. Mais il faut quelque chose de plus pour s'animer. Ceci est un excellent forum, s'il vous plaît dites-moi, comment puis-je surmonter cela.
1) EmpApp.java considèrent juste la méthode getAllEmployee(), omettez le reste.
package test;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import com.mysql.jdbc.PreparedStatement;
public abstract class EmpApp implements Set<Employee>
{
public Set<EmpApp> empobj = new HashSet<EmpApp>();
private Set<Employee> persons = new HashSet<Employee>();
public boolean add(Employee employee) {
return persons.add(employee);
}
public EmpApp(){
}
public Set<EmpApp> getAllEmp()
{
return empobj;
}
public void addEmployee(Employee employee) throws SQLException, ClassNotFoundException
{
int tempID = employee.getId();
String tname = employee.getName();
int tage = employee.getAge();
String tdept = employee.getDept();
PreparedStatement pstmt;
Class.forName("com.mysql.jdbc.Driver");
String url ="jdbc:mysql://localhost:3306/general";
Connection con = DriverManager.getConnection(url,"root", "1234");
System.out.println("URL: " + url);
System.out.println("Connection: " + con);
pstmt = (PreparedStatement) con.prepareStatement("INSERT INTO PERSON SET ID=?, NAME=?, AGE=?, DEPT=?");
pstmt.setInt(1, tempID);
pstmt.setString(2, tname);
pstmt.setInt(3, tempID);
pstmt.setString(4, tdept);
pstmt.executeUpdate();
}
public void updateEmployee(Employee employee) throws SQLException, ClassNotFoundException
{
int tempID = employee.getId();
String tname = employee.getName();
int tage = employee.getAge();
String tdept = employee.getDept();
PreparedStatement pstmt;
Class.forName("com.mysql.jdbc.Driver");
String url ="jdbc:mysql://localhost:3306/general";
Connection con = DriverManager.getConnection(url,"root", "1234");
System.out.println("URL: " + url);
System.out.println("Connection: " + con);
pstmt = (PreparedStatement) con.createStatement();
pstmt = (PreparedStatement) con.prepareStatement("UPDATE PERSON SET NAME=?, AGE=?, DEPT=? WHERE ID=?");
pstmt.setInt(2, tage);
pstmt.setString(1, tname);
pstmt.setString(3, tdept);
pstmt.setInt(4, tempID);
pstmt.executeUpdate();
}
public void deleteEmployee(Employee employee) throws ClassNotFoundException, SQLException
{
int eid = employee.getId();
PreparedStatement pstmt;
Class.forName("com.mysql.jdbc.Driver");
String url ="jdbc:mysql://localhost:3306/general";
Connection con = DriverManager.getConnection(url,"root", "1234");
System.out.println("URL: " + url);
System.out.println("Connection: " + con);
pstmt = (PreparedStatement) con.createStatement();
pstmt = (PreparedStatement) con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
pstmt.executeUpdate("DELETE FROM PERSON WHERE ID="+eid);
}
@SuppressWarnings("unchecked")
private Set<EmpApp> getAllEmployee() throws ClassNotFoundException, SQLException
{
Employee employee = new Employee();
Statement stmt;
ResultSet rs;
Class.forName("com.mysql.jdbc.Driver");
String url ="jdbc:mysql://localhost:3306/general";
Connection con = DriverManager.getConnection(url,"root", "1234");
System.out.println("URL: " + url);
System.out.println("Connection: " + con);
stmt = con.createStatement();
stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery("SELECT * " + "from person ORDER BY ID");
while(rs.next())
{
String name = rs.getString(2);
employee.setName(name);
int id = rs.getInt(1);
employee.setId(id);
String dept = rs.getString(4);
employee.setDept(dept);
int age = rs.getInt(3);
employee.setAge(age);
empobj.addAll((Collection<? extends EmpApp>) employee);
}
return empobj;
}
}
2) Employee.java
package test;
public class Employee
{
private Set<Employee> employee = new HashSet<Employee>();
public Employee() {
// TODO Auto-generated constructor stub
}
private String name;
private String dept;
private int age;
private int id;
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 = Security.escapeHtml(name);;
}
public int getAge(){
return age;
}
public void setAge(int age){
this.age = age;
}
public String getDept(){
return dept;
}
public void setDept(String dept){
this.dept = Security.escapeHtml(dept);
}
public boolean equals(Object obj){
if (obj == null)
{
return false;
}
if (obj == this)
{
return true;
}
if (!this.getClass().equals(obj.getClass()))
{
return false;
}
Employee that = (Employee) obj;
if (this.id != that.id)
{
return false;
}
return true;
}
public String toString(){
return "Employee[id=" + id + ",name=" + name + "]";
}
}
Le code index.html:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Employee Data</title>
<script type='text/javascript' src='dwr/engine.js'> </script>
<script type='text/javascript' src='dwr/util.js'> </script>
<script type='text/javascript' src='dwr/interface/EmpApp.js'> </script>
<script>
function init() {
showTable();
}
var empCache = { };
var viewed = -1;
function showTable() {
EmpApp.getAllEmployee(function(empobj) {
dwr.util.removeAllRows("EmpRow", { filter:function(tr) {
return (tr.id != "pattern");
}});
var employee, eid;
for (var i = 0; i < empobj.length; i++) {
employee = empobj[i];
eid = empobj.id;
dwr.util.cloneNode("pattern", { idSuffix:id });
dwr.util.setValue("ID" + id, employee.id);
dwr.util.setValue("NAME" + id, employee.name);
dwr.util.setValue("AGE" + id, employee.age);
dwr.util.setValue("DEPT" + id, employee.dept);
$("pattern" + id).style.display = "table-row";
empCache[id] = employee;
}
});
}
</script>
</head>
<body onload="init();">
<div id="tabContents">
<div id="demoDiv">
<h3>Employee</h3>
<table border="1" class="rowed grey">
<thead>
<tr>
<th>ID</th>
<th>NAME</th>
<th>AGE</th>
<th>DEPT</th>
</tr>
</thead>
<tbody id="EmpRow">
<tr id="pattern" style="display:none;">
<td>
<span id="ID">Name</span><br/>
<span id="NAME">Name</span><br/>
<span id="AGE">Age</span>
</td>
<td><span id="DEPT">Dept</span></td>
</tr>
</tbody>
</table>
</div>
</body>
</html>
Bien sûr, son application web asynchrone. J'utilise DWR ici. Le fichier dwr.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC
"-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN"
"http://getahead.org/dwr/dwr20.dtd">
<dwr>
<allow>
<create creator="new" javascript="EmpApp" scope="script">
<param name="class" value="test.EmpApp"/>
<include method="GetAllEmployee"/>
</create>
<convert match="test.EmpApp" converter="bean"/>
</allow>
</dwr>
Et le web.xml final
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>LastDisplay</display-name>
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>