GridBagLayout把一个界面分为m行n列的网格
GridBagConstraints的一个实例：
gridx = 2; // X2,表示组件位于第2列
gridy = 0; // Y0,表示组件位于第0行
gridwidth = 1; // 横占一个单元格,即表示组件占1列
gridheight = 1; // 列占一个单元格，即表示组件占1行
weightx = 0.0; // 当窗口放大时，长度不变
weighty = 0.0; // 当窗口放大时，高度不变
anchor = GridBagConstraints.NORTH; // 当组件没有空间大时，使组件处在北部
fill = GridBagConstraints.BOTH; // 当格子有剩余空间时的填充方式。当前在水平和垂直两个方向填充
insert = new Insets(0, 0, 0, 0); // 组件彼此的间距
ipadx = 0; // 组件内部填充空间，即给组件的最小宽度添加多大的空间
ipady = 0; // 组件内部填充空间，即给组件的最小高度添加多大的空间
new GridBagConstraints(gridx, gridy, gridwidth, gridheight, weightx, weighty, anchor, fill, insert, ipadx, ipady);
http://blog.sina.com.cn/s/blog_4412ae250100062n.html
API:
java.awt.GridBagConstraints.GridBagConstraints(int gridx, int gridy,
int gridwidth, int gridheight,
double weightx, double weighty,
int anchor, int fill, Insets insets, int ipadx, int ipady) Creates a GridBagConstraints object with all of its fields set to the passed-in arguments.
Note: Because the use of this constructor hinders readability of source code,
this constructor should only be used by automatic source code generation tools. Parameters:
gridx The initial gridx value.
gridy The initial gridy value.
gridwidth The initial gridwidth value.
gridheight The initial gridheight value.
weightx The initial weightx value.
weighty The initial weighty value.
anchor The initial anchor value.
fill The initial fill value.
insets The initial insets value.
ipadx The initial ipadx value.
ipady The initial ipady value.
package swing.mail; import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Scanner; import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingWorker; /*2015-7-7*/
public class MailTest {
public static void main(String[] args) {
JFrame frame = new MailTestFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
} } class MailTestFrame extends JFrame {
private static final long serialVersionUID = 1L; private Scanner in;
private PrintWriter out;
private JTextField from;
private JTextField to;
private JTextField smtpServer;
private JTextArea message;
private JTextArea comm; public static final int DEFAULT_WIDTH = 300;
public static final int DEFAULT_HEIGHT = 300; public MailTestFrame() {
setTitle("MailTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); setLayout(new GridBagLayout()); add(new JLabel("From:"), new GBC(0, 0).setFill(GBC.HORIZONTAL)); from = new JTextField(20);
add(from, new GBC(1, 0).setFill(GBC.HORIZONTAL).setWeight(100, 0)); add(new JLabel("To:"), new GBC(0, 1).setFill(GBC.HORIZONTAL)); to = new JTextField(20);
add(to, new GBC(1, 1).setFill(GBC.HORIZONTAL).setWeight(100, 0)); add(new JLabel("SMTP server:"), new GBC(0, 2).setFill(GBC.HORIZONTAL)); smtpServer = new JTextField(20);
add(smtpServer, new GBC(1, 2).setFill(GBC.HORIZONTAL).setWeight(100, 0)); message = new JTextArea();
add(new JScrollPane(message), new GBC(0, 3, 2, 1).setFill(GBC.BOTH).setWeight(100, 100)); comm = new JTextArea();
add(new JScrollPane(comm), new GBC(0, 4, 2, 1).setFill(GBC.BOTH).setWeight(100, 100)); JPanel buttonPanel = new JPanel();
add(buttonPanel, new GBC(0, 5, 2, 1)); JButton sendButton = new JButton("Send");
buttonPanel.add(sendButton);
sendButton.addActionListener(new ActionListener() { @Override
public void actionPerformed(ActionEvent e) {
new SwingWorker<Void, Void>() { @Override
protected Void doInBackground() throws Exception {
comm.setText("");
sendMail();
return null;
}
}.execute(); }
}); } public void sendMail() {
try {
Socket s = new Socket(smtpServer.getText(), 25);
InputStream inputStream = s.getInputStream();
OutputStream outputStream = s.getOutputStream(); in = new Scanner(inputStream);
out = new PrintWriter(outputStream, true); String hostName = InetAddress.getLocalHost().getHostName();
receive();
send("Hello" + hostName);
receive();
send("Mail From:<" + from.getText() + ">");
receive();
send("RCPT TO:<" + to.getText() + ">");
receive();
send("DATA");
receive();
send(message.getText());
send(".");
receive();
s.close();
} catch (Exception e) {
comm.append("Error:" + e); } } private void send(String string) {
comm.append(string);
comm.append("\n");
out.println(string.replace("\n", "\r\n"));
out.print("\r\n");
out.flush();
} private void receive() {
String line = in.nextLine();
comm.append(line);
comm.append("\n");
} }
package swing.mail; import java.awt.GridBagConstraints; /**
* This class simplifies the use of the GridBagConstraints class.
*/
public class GBC extends GridBagConstraints
{
private static final long serialVersionUID = 1L; /**
* Constructs a GBC with a given gridx and gridy position and all other grid
* bag constraint values set to the default.
*
* @param gridx
* the gridx position
* @param gridy
* the gridy position
*/
public GBC(int gridx, int gridy)
{
this.gridx = gridx;
this.gridy = gridy;
} /**
* Constructs a GBC with given gridx, gridy, gridwidth, gridheight and all
* other grid bag constraint values set to the default.
*
* @param gridx
* the gridx position
* @param gridy
* the gridy position
* @param gridwidth
* the cell span in x-direction
* @param gridheight
* the cell span in y-direction
*/
public GBC(int gridx, int gridy, int gridwidth, int gridheight) {
this.gridx = gridx;
this.gridy = gridy;
this.gridwidth = gridwidth;
this.gridheight = gridheight;
} /**
* Sets the cell spans.
*
* @param gridwidth
* the cell span in x-direction
* @param gridheight
* the cell span in y-direction
* @return this object for further modification
*/
public GBC setSpan(int gridwidth, int gridheight)
{
this.gridwidth = gridwidth;
this.gridheight = gridheight;
return this;
} /**
* Sets the anchor.
*
* @param anchor
* the anchor value
* @return this object for further modification
*/
public GBC setAnchor(int anchor)
{
this.anchor = anchor;
return this;
} /**
* Sets the fill direction.
*
* @param fill
* the fill direction
* @return this object for further modification
*/
public GBC setFill(int fill)
{
this.fill = fill;
return this;
} /**
* Sets the cell weights.
*
* @param weightx
* the cell weight in x-direction
* @param weighty
* the cell weight in y-direction
* @return this object for further modification
*/
public GBC setWeight(double weightx, double weighty)
{
this.weightx = weightx;
this.weighty = weighty;
return this;
} /**
* Sets the insets of this cell.
*
* @param distance
* the spacing to use in all directions
* @return this object for further modification
*/
public GBC setInsets(int distance)
{
this.insets = new java.awt.Insets(
distance, distance, distance, distance);
return this;
} /**
* Sets the insets of this cell.
*
* @param top
* the spacing to use on top
* @param left
* the spacing to use to the left
* @param bottom
* the spacing to use on the bottom
* @param right
* the spacing to use to the right
* @return this object for further modification
*/
public GBC setInsets(int top, int left, int bottom, int right)
{
this.insets = new java.awt.Insets(
top, left, bottom, right);
return this;
} /**
* Sets the internal padding
*
* @param ipadx
* the internal padding in x-direction
* @param ipady
* the internal padding in y-direction
* @return this object for further modification
*/
public GBC setIpad(int ipadx, int ipady)
{
this.ipadx = ipadx;
this.ipady = ipady;
return this;
}
}
http://bbs.csdn.net/topics/300244821