添加查看jre

Tools/viewjre/JreViewer.cs

@@ -0,0 +1,48 @@
+using System;
+using System.IO;
+using System.Linq;
+
+namespace MCSJ.Tools.ViewJre
+{
+    public class JreViewer
+    {
+        private const string SetupFolder = "setup";
+        private const string JreTomlFile = "jre.toml";
+
+        public void DisplayInstalledJres()
+        {
+            var tomlPath = Path.Combine(SetupFolder, JreTomlFile);
+            
+            if (!File.Exists(tomlPath))
+            {
+                Console.WriteLine("没有安装任何JRE");
+                return;
+            }
+
+            try
+            {
+                var content = File.ReadAllText(tomlPath);
+                var versions = content.Split('\n')
+                    .Where(line => line.StartsWith("[jre."))
+                    .Select(line => line.Split('.')[1].Split(']')[0].Trim()) // 精确提取版本号
+                    .ToList();
+
+                if (versions.Count == 0)
+                {
+                    Console.WriteLine("没有安装任何JRE");
+                    return;
+                }
+
+                Console.WriteLine("已安装的JRE版本:");
+                foreach (var version in versions)
+                {
+                    Console.WriteLine(version); // 直接输出版本号，不带前缀
+                }
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine($"读取JRE列表失败: {ex.Message}");
+            }
+        }
+    }
+}