Affichage des Enregistrements De Base de données MySQL à l'aide de JTable en Java

Ci-dessous est une classe qui permettra d'accomplir l'essentiel de ce que vous voulez faire lors de la lecture de données à partir d'une base de données MySQL dans un JTable en Java.

import java.awt.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
public class TableFromMySqlDatabase extends JFrame
{
public TableFromMySqlDatabase()
{
ArrayList columnNames = new ArrayList();
ArrayList data = new ArrayList();
// Connect to an MySQL Database, run query, get result set
String url = "jdbc:mysql://localhost:3306/yourdb";
String userid = "root";
String password = "sesame";
String sql = "SELECT * FROM animals";
//Java SE 7 has try-with-resources
//This will ensure that the sql objects are closed when the program 
//is finished with them
try (Connection connection = DriverManager.getConnection( url, userid, password );
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery( sql ))
{
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.add( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
ArrayList row = new ArrayList(columns);
for (int i = 1; i <= columns; i++)
{
row.add( rs.getObject(i) );
}
data.add( row );
}
}
catch (SQLException e)
{
System.out.println( e.getMessage() );
}
//Create Vectors and copy over elements from ArrayLists to them
//Vector is deprecated but I am using them in this example to keep 
//things simple - the best practice would be to create a custom defined
//class which inherits from the AbstractTableModel class
Vector columnNamesVector = new Vector();
Vector dataVector = new Vector();
for (int i = 0; i < data.size(); i++)
{
ArrayList subArray = (ArrayList)data.get(i);
Vector subVector = new Vector();
for (int j = 0; j < subArray.size(); j++)
{
subVector.add(subArray.get(j));
}
dataVector.add(subVector);
}
for (int i = 0; i < columnNames.size(); i++ )
columnNamesVector.add(columnNames.get(i));
// Create table with database data    
JTable table = new JTable(dataVector, columnNamesVector)
{
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
JScrollPane scrollPane = new JScrollPane( table );
getContentPane().add( scrollPane );
JPanel buttonPanel = new JPanel();
getContentPane().add( buttonPanel, BorderLayout.SOUTH );
}
public static void main(String[] args)
{
TableFromMySqlDatabase frame = new TableFromMySqlDatabase();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible(true);
}
}

Dans NetBeans IDE que vous utilisez, vous aurez besoin d'ajouter le Pilote JDBC MySQL dans les Propriétés du Projet, comme je l'affiche ici:

Sinon, le code va jeter un SQLException indiquant que le pilote ne peut pas être trouvé.

Maintenant dans mon exemple, yourdb est le nom de la base de données et animals est le nom de la table que je suis l'exécution d'une requête contre.

Ici est ce qui va être de sortie:

De joint note:

Vous avez dit que vous étiez un novice et besoin d'un peu d'aide pour comprendre certaines des classes de base et les concepts de Java. Je vais en citer quelques-uns ici, mais n'oubliez pas que vous pouvez toujours parcourir les docs sur Oracle du site.

• ArrayList
• Vecteur
• Try-with-resources déclaration

OriginalL'auteur Derek W

Si vous avez besoin de beaucoup travailler avec la base de données dans votre code et vous connaissez la structure de votre table, je vous suggère de le faire comme suit:

Tout d'abord, vous pouvez définir une classe qui va vous aider à faire des objets capables de garder les lignes de votre tableau de données. Par exemple dans mon projet, j'ai créé une classe nommée Document.java de conserver les données d'un document unique à partir de ma base de données et j'ai fait un tableau de la liste de ces objets à conserver les données de mon tableau qui est le gain par une requête.

package financialdocuments;
import java.lang.*;
import java.util.HashMap;
/**
*
* @author Administrator
*/
public class Document {
private int document_number; 
private boolean document_type;
private boolean document_status; 
private StringBuilder document_date;
private StringBuilder document_statement;
private int document_code_number;
private int document_employee_number;
private int document_client_number;
private String document_employee_name;
private String document_client_name;
private long document_amount;
private long document_payment_amount;
HashMap<Integer,Activity> document_activity_hashmap;
public Document(int dn,boolean dt,boolean ds,String dd,String dst,int dcon,int den,int dcln,long da,String dena,String dcna){
document_date = new StringBuilder(dd);
document_date.setLength(10);
document_date.setCharAt(4, '.');
document_date.setCharAt(7, '.');
document_statement = new StringBuilder(dst);
document_statement.setLength(50);
document_number = dn; 
document_type = dt;
document_status = ds;
document_code_number = dcon;
document_employee_number = den;
document_client_number = dcln;
document_amount = da;
document_employee_name = dena;
document_client_name = dcna;
document_payment_amount = 0;
document_activity_hashmap = new HashMap<>();
}
public Document(int dn,boolean dt,boolean ds, long dpa){
document_number = dn; 
document_type = dt;
document_status = ds;
document_payment_amount = dpa;
document_activity_hashmap = new HashMap<>();
}
//Print document information 
public void printDocumentInformation (){
System.out.println("Document Number:" + document_number); 
System.out.println("Document Date:" + document_date); 
System.out.println("Document Type:" + document_type); 
System.out.println("Document Status:" + document_status); 
System.out.println("Document Statement:" + document_statement); 
System.out.println("Document Code Number:" + document_code_number); 
System.out.println("Document Client Number:" + document_client_number); 
System.out.println("Document Employee Number:" + document_employee_number); 
System.out.println("Document Amount:" + document_amount); 
System.out.println("Document Payment Amount:" + document_payment_amount); 
System.out.println("Document Employee Name:" + document_employee_name); 
System.out.println("Document Client Name:" + document_client_name); 
} 
} 

Deuxième de tous, vous pouvez définir une classe permettant de gérer votre base de données. Par exemple, j'ai défini une classe nommée DataBase.java qui s'occupe de mon connexions à la base de données et mon besoin de requêtes. Et j'ai instancié à l'opposé de ma classe principale.

package financialdocuments;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*
* @author Administrator
*/
public class DataBase {
/** 
* 
* Defining parameters and strings that are going to be used
* 
*/
//Connection connect;
//Tables which their datas are extracted at the beginning 
HashMap<Integer,String> code_table;
HashMap<Integer,String> activity_table;
HashMap<Integer,String> client_table;
HashMap<Integer,String> employee_table;
//Resultset Returned by queries 
private ResultSet result;
//Strings needed to set connection
String url = "jdbc:mysql://localhost:3306/financial_documents?useUnicode=yes&characterEncoding=UTF-8";
String dbName = "financial_documents";
String driver = "com.mysql.jdbc.Driver";
String userName = "root"; 
String password = "";
public DataBase(){
code_table = new HashMap<>();
activity_table = new HashMap<>();
client_table = new HashMap<>();
employee_table = new HashMap<>();
Initialize();
}
/**
* Set variables and objects for this class.
*/
private void Initialize(){
System.out.println("Loading driver..."); 
try {
Class.forName(driver);
System.out.println("Driver loaded!"); 
} catch (ClassNotFoundException e) { 
throw new IllegalStateException("Cannot find the driver in the classpath!", e); 
}
System.out.println("Connecting database...");
try (Connection connect = DriverManager.getConnection(url,userName,password)) {
System.out.println("Database connected!");
//Get tables' information 
selectCodeTableQueryArray(connect);
//System.out.println("HshMap Print:");
//printCodeTableQueryArray();
selectActivityTableQueryArray(connect);
//System.out.println("HshMap Print:");
//printActivityTableQueryArray(); 
selectClientTableQueryArray(connect);
//System.out.println("HshMap Print:");
//printClientTableQueryArray();
selectEmployeeTableQueryArray(connect);
//System.out.println("HshMap Print:");
//printEmployeeTableQueryArray();
connect.close();
}catch (SQLException e) { 
throw new IllegalStateException("Cannot connect the database!", e);
}
} 
/**
* Write Queries 
* @param s
* @return 
*/
public boolean insertQuery(String s){
boolean ret = false;
System.out.println("Loading driver..."); 
try {
Class.forName(driver);
System.out.println("Driver loaded!"); 
} catch (ClassNotFoundException e) { 
throw new IllegalStateException("Cannot find the driver in the classpath!", e); 
}
System.out.println("Connecting database...");
try (Connection connect = DriverManager.getConnection(url,userName,password)) {
System.out.println("Database connected!");
//Set tables' information 
try {
Statement st = connect.createStatement();
int val = st.executeUpdate(s);
if(val==1){ 
System.out.print("Successfully inserted value");
ret = true;
}
else{ 
System.out.print("Unsuccessful insertion");
ret = false;
}
st.close();
} catch (SQLException ex) {
Logger.getLogger(DataBase.class.getName()).log(Level.SEVERE, null, ex);
}
connect.close();
}catch (SQLException e) { 
throw new IllegalStateException("Cannot connect the database!", e);
} 
return ret;
}
/**
* Query needed to get code table's data
* @param c
* @return 
*/
private void selectCodeTableQueryArray(Connection c) {
try {
Statement st = c.createStatement();
ResultSet res = st.executeQuery("SELECT * FROM  code;");
while (res.next()) {
int id = res.getInt("code_number");
String msg = res.getString("code_statement");
code_table.put(id, msg);
}
st.close();
} catch (SQLException ex) {
Logger.getLogger(DataBase.class.getName()).log(Level.SEVERE, null, ex);
}
}
private void printCodeTableQueryArray() {
for (HashMap.Entry<Integer ,String> entry : code_table.entrySet()){
System.out.println("Key : " + entry.getKey() + " Value : " + entry.getValue());
}
}
/**
* Query needed to get activity table's data
* @param c
* @return 
*/
private void selectActivityTableQueryArray(Connection c) {
try {
Statement st = c.createStatement();
ResultSet res = st.executeQuery("SELECT * FROM  activity;");
while (res.next()) {
int id = res.getInt("activity_number");
String msg = res.getString("activity_statement");
activity_table.put(id, msg);
}
st.close();
} catch (SQLException ex) {
Logger.getLogger(DataBase.class.getName()).log(Level.SEVERE, null, ex);
}
}
private void printActivityTableQueryArray() {
for (HashMap.Entry<Integer ,String> entry : activity_table.entrySet()){
System.out.println("Key : " + entry.getKey() + " Value : " + entry.getValue());
}
}
/**
* Query needed to get client table's data
* @param c
* @return 
*/
private void selectClientTableQueryArray(Connection c) {
try {
Statement st = c.createStatement();
ResultSet res = st.executeQuery("SELECT * FROM  client;");
while (res.next()) {
int id = res.getInt("client_number");
String msg = res.getString("client_full_name");
client_table.put(id, msg);
}
st.close();
} catch (SQLException ex) {
Logger.getLogger(DataBase.class.getName()).log(Level.SEVERE, null, ex);
}
}
private void printClientTableQueryArray() {
for (HashMap.Entry<Integer ,String> entry : client_table.entrySet()){
System.out.println("Key : " + entry.getKey() + " Value : " + entry.getValue());
}
}
/**
* Query needed to get activity table's data
* @param c
* @return 
*/
private void selectEmployeeTableQueryArray(Connection c) {
try {
Statement st = c.createStatement();
ResultSet res = st.executeQuery("SELECT * FROM  employee;");
while (res.next()) {
int id = res.getInt("employee_number");
String msg = res.getString("employee_full_name");
employee_table.put(id, msg);
}
st.close();
} catch (SQLException ex) {
Logger.getLogger(DataBase.class.getName()).log(Level.SEVERE, null, ex);
}
}
private void printEmployeeTableQueryArray() {
for (HashMap.Entry<Integer ,String> entry : employee_table.entrySet()){
System.out.println("Key : " + entry.getKey() + " Value : " + entry.getValue());
}
} 
}

J'espère que cela pourrait être un peu d'aide.

OriginalL'auteur Sparrow7000