在 Java 中使用 JTable 显示 MySQL 数据库中的记录

Question

我想从 MySQL 数据库将 JTable 连接到 ResultSet，以便查看数据。

我正在寻找一些描述此任务的链接或代码 sn-ps。我正在使用 Netbeans IDE..

Answer 1

下面是一个类，它将完成您在将数据从 MySQL 数据库读取到 Java 中的 JTable 时想要执行的基本操作。

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);
    }
}

在您使用的 NetBeans IDE 中 - 您需要在项目属性中添加 MySQL JDBC 驱动程序，如下所示：

否则代码将抛出一个SQLException 说明找不到驱动程序。

现在在我的示例中，yourdb 是数据库的名称，animals 是我正在执行查询的表的名称。

以下是输出内容：

离别说明：

您说您是新手，需要一些帮助来理解 Java 的一些基本类和概念。我将在这里列出一些，但请记住，您可以随时浏览 Oracle 网站上的文档。

• ArrayList
• Vector
• Try-with-resources statement

Answer 2

这是一种简单的方法，您只需下载 jar 文件 "rs2xml.jar" 将其添加到您的项目中 并这样做： 1-创建连接 2- 语句和结果集 3-创建一个jtable 4-将结果集提供给DbUtils.resultSetToTableModel(rs) 正如在这个方法中定义的那样，你很容易得到你的 jtable。

public void afficherAll(String tableName){
        String sql="select * from "+tableName;
        try {
            stmt=con.createStatement();
            rs=stmt.executeQuery(sql);
            tbContTable.setModel(DbUtils.resultSetToTableModel(rs));
        } catch (SQLException e) {
            // TODO Auto-generated catch block
             JOptionPane.showMessageDialog(null, e);
        }       
    }

Answer 3

如果您需要在代码中大量使用数据库并且您知道表的结构，我建议您按照以下方式进行操作：

首先，您可以定义一个类，该类将帮助您制作能够保存表格行数据的对象。例如，在我的项目中，我创建了一个名为 Document.java 的类来保存数据库中单个文档的数据，并制作了这些对象的数组列表来保存我的表的数据，该数据由查询。

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); 

} 
} 

其次，您可以定义一个类来处理您的数据库需求。例如，我定义了一个名为 DataBase.java 的类，它处理我与数据库的连接以及我需要的查询。我在我的主类中实例化了一个反对它。

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());
    }
} 
}

我希望这可以提供一点帮助。