System default locale

mirai-core-api/src/commonMain/kotlin/internal/utils/StdoutLogger.kt

@@ -10,7 +10,6 @@
 package net.mamoe.mirai.internal.utils
 
 import net.mamoe.mirai.utils.*
-import java.text.DateFormat
 import java.text.SimpleDateFormat
 import java.util.*
 
@@ -102,7 +101,9 @@ internal open class StdoutLogger constructor(
         else debug(message.toString())
     }
 
-    protected open val timeFormat: DateFormat = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.SIMPLIFIED_CHINESE)
+    protected open val timeFormat: SimpleDateFormat by threadLocal {
+        SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault())
+    }
 
     private val currentTimeFormatted get() = timeFormat.format(Date())
 

mirai-core-api/src/jvmMain/kotlin/utils/PlatformLogger.jvm.kt

@@ -13,6 +13,8 @@ package net.mamoe.mirai.utils
 
 import java.text.DateFormat
 import java.text.SimpleDateFormat
+import java.time.LocalDateTime
+import java.time.format.DateTimeFormatter
 import java.util.*
 
 /**
@@ -106,9 +108,12 @@ public actual open class PlatformLogger constructor(  // same as StdoutLogger bu
         else debug(message.toString())
     }
 
+    @Deprecated("Use formatter instead.", level = DeprecationLevel.HIDDEN)
     protected open val timeFormat: DateFormat = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.SIMPLIFIED_CHINESE)
 
-    private val currentTimeFormatted get() = timeFormat.format(Date())
+    protected open val formatter: DateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
+
+    private val currentTimeFormatted get() = formatter.format(LocalDateTime.now())
 
     @MiraiExperimentalApi("This is subject to change.")
     protected enum class Color(private val format: String) {

mirai-core-utils/src/commonMain/kotlin/ThreadLocal.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/dev/LICENSE
+ */
+
+package net.mamoe.mirai.utils
+
+import kotlin.reflect.KProperty
+
+
+public fun <T : Any?> threadLocal(newInstance: () -> T): ThreadLocal<T> {
+    return object : ThreadLocal<T>() {
+        override fun initialValue(): T = newInstance()
+    }
+}
+
+public operator fun <T> ThreadLocal<T>.getValue(t: Any?, property: KProperty<Any?>): T = this.get()