如何在Java中设置和获取线程优先级？

查看和修改线程优先级

1.题目

JAVA中每个线程都有优化级属性，默认情况下，新建的线程和创建该线程的线程优先级是一样的。当线程调度器选择要运行的线程时，会选择优先级高的线程。

实现：查看和修改线程的优先级

2.解题思路

创建一个类：ThreadPriorityTest，继承了JFrame。用来界面显示当前线程组中运行的线程。

定义2个方法：

• do_this_windowActivated():用来监听窗体激活事件

• do_button_actionPerformed() :用来单击修改按钮事件，获取用户输入的优先级和选择的行，修改线程优先级。

Thread是程序中的执行线程。JAVA虚拟机允许应用程序并发地运行多个执行线程。

3.代码详解

package com.xiaoxuzhu;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.border.EmptyBorder;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
/**
 * Description: 
 *
 * @author xiaoxuzhu
 * @version 1.0
 *
 * <pre class="brush:php;toolbar:false">
 * 修改记录:
 * 修改后版本	        修改人		修改日期			修改内容
 * 2022/5/11.1	    xiaoxuzhu		2022/5/11		    Create
 * 

* @date 2022/5/11 */ public class ThreadPriorityTest extends JFrame { /** * */ private static final long serialVersionUID = 1127454227002083871L; private JPanel contentPane; private JTable table; private JTextField textField; /** * Launch the application. */ public static void main(String[] args) { try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"); } catch (Throwable e) { e.printStackTrace(); } EventQueue.invokeLater(new Runnable() { public void run() { try { ThreadPriorityTest frame = new ThreadPriorityTest(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the frame. */ public ThreadPriorityTest() { addWindowListener(new WindowAdapter() { @Override public void windowActivated(WindowEvent e) { do_this_windowActivated(e); } }); setTitle("查看和修改线程优化级"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 450, 300); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); contentPane.setLayout(new BorderLayout(0, 0)); setContentPane(contentPane); JPanel panel = new JPanel(); contentPane.add(panel, BorderLayout.SOUTH); JLabel label = new JLabel("新优先级（1~10）"); label.setFont(new Font("微软雅黑", Font.PLAIN, 16)); panel.add(label); textField = new JTextField(); textField.setFont(new Font("微软雅黑", Font.PLAIN, 16)); panel.add(textField); textField.setColumns(10); JButton button = new JButton("修改"); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { do_button_actionPerformed(e); } }); button.setFont(new Font("微软雅黑", Font.PLAIN, 16)); panel.add(button); JScrollPane scrollPane = new JScrollPane(); contentPane.add(scrollPane, BorderLayout.CENTER); table = new JTable(); table.setFont(new Font("微软雅黑", Font.PLAIN, 14)); table.setRowHeight(30); JTableHeader header = table.getTableHeader(); header.setFont(new Font("微软雅黑", Font.PLAIN, 16)); header.setPreferredSize(new Dimension(header.getWidth(), 35)); scrollPane.setViewportView(table); } protected void do_this_windowActivated(WindowEvent e) { ThreadGroup group = Thread.currentThread().getThreadGroup();// 获得当前线程所在线程组 Thread[] threads = new Thread[group.activeCount()];// 使用数组保存活动状态的线程 group.enumerate(threads);// 获得所有线程 DefaultTableModel model = (DefaultTableModel) table.getModel(); // 获得表格模型 model.setRowCount(0); // 清空表格模型中的数据 model.setColumnIdentifiers(new Object[] { "线程ID", "线程名称", "优先级" }); // 定义表头 for (Thread thread : threads) {// 增加行数据 model.addRow(new Object[] { thread.getId(), thread.getName(), thread.getPriority() }); } table.setModel(model);// 更新表格模型 } protected void do_button_actionPerformed(ActionEvent e) { String text = textField.getText(); Integer priority = Integer.parseInt(text); int selectedRow = table.getSelectedRow(); DefaultTableModel model = (DefaultTableModel) table.getModel(); model.setValueAt(priority, selectedRow, 2); repaint(); } }

线程列表和对应优先级：

修改线程优先级：

修改结果：

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