下面登录界面怎么设置背景图，不覆盖控件。

Question

package com.view;

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import com.db.SqlHelper;

public class LoginView extends JFrame{

private JPanel centerJpanel;
private JTextField userName;
private JPasswordField password;

private JPanel southJpanel;
private JButton loginBtn;
private JButton regiestBtn;


public LoginView() {
    setTitle("登录");

    buildUi();

    setSize(400, 200);
    setLocationRelativeTo(null);
    setResizable(false);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
}

/**
 * 初使化界面
 */
public void buildUi(){
    setLayout(new BorderLayout(20,20));
    //实例化中间容器
    centerJpanel = new JPanel();

    //实例化用户名密码控件
    userName = new JTextField(20);
    password = new JPasswordField(20);

    //添加用户名密码控件到 中间容器中
    centerJpanel.add(userName);
    centerJpanel.add(password);

    //实列化欢迎字，并添加到根容器的北边
    JLabel welcomeJL = new JLabel("欢迎使用xxx销售管理系统！");
    welcomeJL.setHorizontalAlignment(JLabel.CENTER);
    add(welcomeJL,BorderLayout.NORTH);
    //添加中间容器到根容器的中间
    add(centerJpanel,BorderLayout.CENTER);

    southJpanel = new JPanel();
    regiestBtn = new JButton("注册");
    regiestBtn.setSize(100, 60);
    southJpanel.add(regiestBtn);
    regiestBtn.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            new RegiestView();

        }
    });

    loginBtn = new JButton("登录");
    loginBtn.setSize(100, 60);
    southJpanel.add(loginBtn);
    loginBtn.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {

            try {
                doLogin();
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }
    });
    add(southJpanel,BorderLayout.SOUTH);
}

private void doLogin() throws SQLException{
    String username = userName.getText().trim();
    String password = this.password.getText().trim();

    String sql = "select * from EmployeeInfo "
            + "where eid=? and password=? and isAdmin=1";

    SqlHelper sqlHelper = new SqlHelper();
    ResultSet result = sqlHelper.
            query(sql, new String[]{username,password});
    if (result.next()) {
        //登录成功
        new SystemMainView();
        dispose();
    }

}

public static void main(String[] args) {
    new LoginView();
}

}

Answer 1

http://blog.csdn.net/lishmoshou/article/details/8100120