当我在表单中插入数据并提交时，我收到了我刚刚更新的信息，并且消息“用户更新成功！”也显示在浏览器上，但是当我检查我的数据库时，我发现相同的信息我之前保持不变，没有任何变化，并且控制台上弹出消息“没有用户更新”。
我尝试检查我的数据库字段和 servlet，但仍然找不到问题。 这是我修改表单时发生的情况：
（ID 7 NOM doe PRENOM jhon 年龄 25 密码 jhon123 电子邮件 [email protected] IDROLE 2 用户更新成功！）
请问问题出在哪里？
这是我的 servlet 代码：
`protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
String idutilisateurStr = request.getParameter("idutilisateur");
int idutilisateur = -1;
if (idutilisateurStr != null && !idutilisateurStr.isEmpty()) {
idutilisateur = Integer.parseInt(idutilisateurStr);
}
String nom = request.getParameter("nom");
String prenom = request.getParameter("prenom");
String ageint = request.getParameter("age");
int age = Integer.parseInt(ageint);
String email = request.getParameter("email");
String mot_de_pass = request.getParameter("mot_de_pass");
String idroleStr = request.getParameter("idrole");
int idrole = Integer.parseInt(idroleStr);
Role role = new Role(idrole);
PrintWriter out = response.getWriter();
Utilisateurs newUtilisateur = new Utilisateurs(idutilisateur, nom, prenom, age, email, mot_de_pass, role);
System.out.println(newUtilisateur);
out.print("ID " + idutilisateur + "<br> ");
out.print("NAM " + nom + "<br> ");
out.print("FIRST NAME " + prenom + " <br>");
out.print("AGE " + age + "<br> ");
out.print("PASSWORD " + mot_de_pass + "<br> ");
out.print("EMAIL " + email + " <br>");
out.print("IDROLE " + idrole + "<br> ");
try {
UserDAO.updateUser(newUtilisateur);
response.getWriter().println("User updated successfully!");
} catch (SQLException e) {
e.printStackTrace();
response.getWriter().println("Error updating user: " + e.getMessage());
}
} catch (NumberFormatException e) {
e.printStackTrace();
response.getWriter().println("Invalid input format: " + e.getMessage());
}
}`
这是我的表格：
<form action = "UpdateServlet" method= "post">
idUtilisateur<input type="number" name="idutilisateur" value="${user.idUtilisateurs}" /><br>
Nom<input type="text" name = "nom" /><br>
Prenom<input type="text" name = "prenom" /><br>
Age<input type="number" name = "age" /><br>
Email<input type="email" name = "email" /><br>
Password<input type="password" name = "mot_de_pass" /><br>
Idrole
<select name="idrole">
<option value="1"> Admin <option>
<option value="2">Client </option>
</select>
<input type="submit" value = "submit"/>
</form>
这是 DAO :
private static final String Update_user = "UPDATE utilisateur SET
idutilisateur = ? ,nom = ? ,prenom=? , age = ?,email = ? , mot_de_pass = ? , idrole = ?"
+ " WHERE idutilisateur = ?";
`public static void updateUser(Utilisateurs u) throws SQLException {
try (Connection connection = Conx();
PreparedStatement preparedStatement = connection.prepareStatement(Update_user)) {
preparedStatement.setInt(1, u.getIdUtilisateurs());
preparedStatement.setString(2, u.getNom());
preparedStatement.setString(3, u.getPrenom());
preparedStatement.setInt(4, u.getAge());
preparedStatement.setString(5, u.getEmail());
preparedStatement.setString(6, u.getPassword());
preparedStatement.setInt(7, u.getRole().getIdRole());
preparedStatement.setInt(8, u.getIdUtilisateurs());
int rowsUpdated = preparedStatement.executeUpdate();
if (rowsUpdated > 0) {
connection.commit();
System.out.println("User updated successfully!");
} else {
System.out.println("No user was updated.");
}
} catch (SQLException e) {
e.printStackTrace();
}
}
这是编辑页面的链接：
<a href="UpdateForm.jsp?idutilisateur=${user.idUtilisateurs}">Edit</a>
您在问题中没有发布足够的信息供我们做出诊断。但我可以给你一些提示和一些示例代码。
两个关键提示：
这里是一些使用 H2 数据库引擎的示例代码。
package work.basil.example.db;
import org.h2.jdbcx.JdbcDataSource;
import javax.sql.DataSource;
import java.sql.*;
import java.time.Instant;
import java.util.Collection;
import java.util.List;
public class FrenchUsers
{
public static void main ( String[] args )
{
FrenchUsers app = new FrenchUsers ( );
app.demo ( );
}
private void demo ( )
{
final DataSource dataSource = this.obtainDataSource ( );
this.prepareDatabase ( dataSource );
this.populateDatabase ( dataSource , this.sampleData ( ) );
this.dumpToConsole ( dataSource );
this.modifyOneRowByRoleCode ( dataSource );
this.dumpToConsole ( dataSource );
}
private DataSource obtainDataSource ( )
{
org.h2.jdbcx.JdbcDataSource ds = new JdbcDataSource ( ); // An implementation of `javax.sql.DataSource` bundled with H2.
ds.setURL ( "jdbc:h2:mem:ex_french_users_db;DB_CLOSE_DELAY=-1" );
ds.setUser ( "scott" );
ds.setPassword ( "tiger" );
ds.setDescription ( "An example database showing how to modify a row per changes to an object." );
return ds;
}
private void prepareDatabase ( DataSource dataSource )
{
System.out.println ( "INFO - Running `prepareDatabase` method. " + Instant.now ( ) );
String sql = """
CREATE TABLE IF NOT EXISTS utilisateur_
(
id_ INTEGER NOT NULL ,
nom_ TEXT NOT NULL ,
prenom_ TEXT NOT NULL ,
age_ INTEGER NOT NULL ,
email_ TEXT NOT NULL ,
mot_de_passe_ TEXT NOT NULL ,
role_code_ INTEGER NOT NULL ,
CONSTRAINT id_ PRIMARY KEY ( id_ )
)
;
""";
try (
Connection conn = dataSource.getConnection ( ) ;
Statement stmt = conn.createStatement ( ) ;
)
{
stmt.executeUpdate ( sql );
}
catch ( SQLException e ) { e.printStackTrace ( ); }
}
private Collection < Utilisateur > sampleData ( )
{
System.out.println ( "INFO - Running `sampleData` method. " + Instant.now ( ) );
return List.of (
new Utilisateur ( 11 , "Abadie" , "Alice" , 49 , "[email protected]" , "123" , 7 ) ,
new Utilisateur ( 12 , "Beaulieu" , "Bob" , 22 , "[email protected]" , "letmein" , 42 ) ,
new Utilisateur ( 13 , "Charbonnier" , "Carol" , 72 , "[email protected]" , "password" , 7 ) );
}
private void populateDatabase ( final DataSource dataSource , final Collection < Utilisateur > originalData )
{
System.out.println ( "INFO - Running `populateDatabase` method. " + Instant.now ( ) );
String sql = """
INSERT INTO utilisateur_ ( id_ , nom_ , prenom_ , age_ , email_ , mot_de_passe_ ,role_code_ )
VALUES ( ? , ? , ? , ? , ? , ? , ? )
;
""";
try (
Connection conn = dataSource.getConnection ( ) ;
PreparedStatement preparedStatement = conn.prepareStatement ( sql ) ;
)
{
for ( Utilisateur utilisateur : originalData )
{
preparedStatement.setInt ( 1 , utilisateur.id ( ) );
preparedStatement.setString ( 2 , utilisateur.nom ( ) );
preparedStatement.setString ( 3 , utilisateur.prenom ( ) );
preparedStatement.setInt ( 4 , utilisateur.age ( ) );
preparedStatement.setString ( 5 , utilisateur.email ( ) );
preparedStatement.setString ( 6 , utilisateur.motDePasse ( ) );
preparedStatement.setInt ( 7 , utilisateur.roleCode ( ) );
preparedStatement.executeUpdate ( );
}
}
catch ( SQLException e ) { e.printStackTrace ( ); }
}
private void modifyOneRowByRoleCode ( final DataSource dataSource )
{
System.out.println ( "INFO - Running `modifyOneRowByRoleCode` method. " + Instant.now ( ) );
Utilisateur utilisateur = this.modifiedUtilisateur ( );
String sql = """
UPDATE utilisateur_
SET role_code_ = ?
WHERE id_ = ?
;
""";
try (
Connection conn = dataSource.getConnection ( ) ;
PreparedStatement preparedStatement = conn.prepareStatement ( sql ) ;
)
{
preparedStatement.setInt ( 1 , utilisateur.roleCode ( ) );
preparedStatement.setInt ( 2 , utilisateur.id ( ) );
int countRowsAffected = preparedStatement.executeUpdate ( );
System.out.println ( "DEBUG - SQL UPDATE affected " + countRowsAffected + " rows." );
}
catch ( SQLException e ) { e.printStackTrace ( ); }
}
private Utilisateur modifiedUtilisateur ( )
{
System.out.println ( "INFO - Running `modifiedUtilisateur` method. " + Instant.now ( ) );
Utilisateur vieux = List.copyOf ( this.sampleData ( ) ).get ( 2 );
Utilisateur nouveau = new Utilisateur (
vieux.id ( ) ,
vieux.nom ( ) ,
vieux.prenom ( ) ,
vieux.age ( ) ,
vieux.email ( ) ,
vieux.motDePasse ( ) ,
vieux.roleCode ( ) + ( 99 - vieux.roleCode ( ) ) // Changing the role code number to 99, to update a row in the database.
);
System.out.println ( "vieux = " + vieux );
System.out.println ( "nouveau = " + nouveau );
System.out.println ( vieux.equals ( nouveau ) );
return nouveau;
}
private void dumpToConsole ( final DataSource dataSource )
{
System.out.println ( "INFO - Running `dumpToConsole` method. " + Instant.now ( ) );
String sql = """
SELECT *
FROM utilisateur_
;
""";
try (
Connection conn = dataSource.getConnection ( ) ;
PreparedStatement preparedStatement = conn.prepareStatement ( sql ) ;
)
{
try (
ResultSet resultSet = preparedStatement.executeQuery ( )
)
{
while ( resultSet.next ( ) )
{ // We expect a single row in each result set, for the count.
int id = resultSet.getInt ( 1 );
String nom = resultSet.getString ( 2 );
String prenom = resultSet.getString ( 3 );
int age = resultSet.getInt ( 4 );
String email = resultSet.getString ( 5 );
String motDePasse = resultSet.getString ( 6 );
int roleCode = resultSet.getInt ( 7 );
String line = String.join ( " | " , Integer.toString ( id ) , nom , prenom , Integer.toString ( age ) , email , motDePasse , Integer.toString ( roleCode ) );
System.out.println ( "line = " + line );
}
}
}
catch ( SQLException e ) { throw new RuntimeException ( e ); }
}
}
record Utilisateur(
int id ,
String nom ,
String prenom ,
int age ,
String email ,
String motDePasse ,
// Of course we would *NEVER* actually store a password, not in real work.
int roleCode
) {}