我是数据库项目的新手。 我不知道如何在将 mongodb 连接到数据库服务器后在 Swing 窗口(编辑:JTable)内显示 mongodb 中的集合....请帮我解决这个... 我已经尝试在 sql 中执行此操作,但无法使用 mongodb 执行此操作
JButton btnDisplay = new JButton("display");
btnDisplay.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
// To connect to mongodb server
MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
// Now connect to your databases
DB db = mongoClient.getDB( "test" );
System.out.println("Connect to database successfully");
DBCollection coll = db.getCollection("cars");
DBCursor cursor = coll.find();
}
catch (Exception a) {
a.printStackTrace();
}
}
});
最佳答案
DBCursor意味着要迭代。您可以使用 DBCursor#hasNext()
就像普通的迭代器
一样,而 DBCursor#next()
获取下一个DBObject
。 DBObject
允许您get
像 Map
一样的值,通过传入键
假设我们在 swingtest
数据库中有一个集合表
,其中包含以下文档
{ "_id" : ObjectId("5450700691a43786388fcc8f"), "first" : "Stack", "last" : "Overflow" }
{ "_id" : ObjectId("5450704d91a43786388fcc90"), "first" : "Pee", "last" : "Skillet" }
{ "_id" : ObjectId("5450705a91a43786388fcc91"), "first" : "Hello", "last" : "World" }
{ "_id" : ObjectId("545070b091a43786388fcc92"), "first" : "Mongo", "last" : "DB" }
您实际上还没有指定要对集合执行什么操作,所以假设您要将数据添加到 JTable
中,您可以执行类似的操作
MongoClient mongoClient = null;
DBCursor cursor = null;
try {
mongoClient = new MongoClient( "localhost" , 27017 );
DB db = mongoClient.getDB( "swingtest" );
DBCollection coll = db.getCollection("table");
cursor = coll.find();
String[] columnNames = {"id", "First", "Last"};
DefaultTableModel model = new DefaultTableModel(columnNames, 0);
while(cursor.hasNext()) {
DBObject obj = cursor.next();
String first = (String)obj.get("first");
String last = (String)obj.get("last");
ObjectId id = (ObjectId)obj.get("_id");
model.addRow(new Object[] { id, first, last });
}
table.setModel(model);
cursor.close();
mongoClient.close();
}
对于每次迭代(文档),我们获取 _id
、first
和 last
值,然后创建一行,在其中添加 DefaultTableModel
。在迭代结束时,我们设置 JTable
的模型。
这是完整的示例
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.UnknownHostException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
import org.bson.types.ObjectId;
public class MongoStackoverflow {
private static JTable table;
public static void main(String[] args) {
Runnable runnable = new Runnable() {
public void run() {
table = new JTable(){
@Override
public Dimension getPreferredScrollableViewportSize() {
return new Dimension(300, 150);
}
};
JPanel panel = new JPanel(new BorderLayout());
JButton button = new JButton("Show Data");
button.addActionListener(listener);
panel.add(new JScrollPane(table));
panel.add(button, BorderLayout.PAGE_END);
JOptionPane.showMessageDialog(null, panel);
}
};
SwingUtilities.invokeLater(runnable);
}
static ActionListener listener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
MongoClient mongoClient = null;
DBCursor cursor = null;
try {
mongoClient = new MongoClient( "localhost" , 27017 );
DB db = mongoClient.getDB( "swingtest" );
DBCollection coll = db.getCollection("table");
cursor = coll.find();
String[] columnNames = {"id", "First", "Last"};
DefaultTableModel model = new DefaultTableModel(columnNames, 0);
while(cursor.hasNext()) {
DBObject obj = cursor.next();
String first = (String)obj.get("first");
String last = (String)obj.get("last");
ObjectId id = (ObjectId)obj.get("_id");
model.addRow(new Object[] { id, first, last });
}
table.setModel(model);
cursor.close();
mongoClient.close();
} catch (UnknownHostException ex) {
Logger.getLogger(MongoStackoverflow.class.getName()).log(Level.SEVERE, null, ex);
} finally {
if (cursor!= null) {
cursor.close();
}
if (mongoClient != null) {
mongoClient.close();
}
}
}
};
}
<小时/>
资源
关于java - 将 MongoDB 集合中的数据检索到 Swing JTable 中,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26616072/