学习idea的查看二进制的编译结果

Xikl · May 26, 2020 · 8ece3f9 · 8ece3f9
1 parent 5b44358
commit 8ece3f9
Showing 1 changed file with 55 additions and 0 deletions.
diff --git a/src/test/java/com/ximo/datastructuresinaction/string/StringTest.java b/src/test/java/com/ximo/datastructuresinaction/string/StringTest.java
@@ -0,0 +1,55 @@
+package com.ximo.datastructuresinaction.string;
+
+/**
+ * @author xikl
+ * @date 2020/5/26
+ */
+public class StringTest {
+
+    public static void main(String[] args) {
+        final String s = concatString("1", "2", "a");
+        System.out.println(s);
+    }
+
+    /**
+     * <code>
+     *     // access flags 0x9
+     *   public static concatString(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
+     *     // parameter  s1
+     *     // parameter  s2
+     *     // parameter  s3
+     *    L0
+     *     LINENUMBER 15 L0
+     *     NEW java/lang/StringBuilder
+     *     DUP
+     *     INVOKESPECIAL java/lang/StringBuilder.<init> ()V
+     *     ALOAD 0
+     *     INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
+     *     ALOAD 1
+     *     INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
+     *     ALOAD 2
+     *     INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
+     *     INVOKEVIRTUAL java/lang/StringBuilder.toString ()Ljava/lang/String;
+     *     ARETURN
+     *    L1
+     *     LOCALVARIABLE s1 Ljava/lang/String; L0 L1 0
+     *     LOCALVARIABLE s2 Ljava/lang/String; L0 L1 1
+     *     LOCALVARIABLE s3 Ljava/lang/String; L0 L1 2
+     *     MAXSTACK = 2
+     *     MAXLOCALS = 3
+     * }
+     * </code>
+     * 会转化为StringBuilder来操作
+     *
+     * @param s1
+     * @param s2
+     * @param s3
+     * @return
+     */
+    public static String concatString(String s1, String s2, String s3) {
+        return s1 + s2 + s3;
+    }
+
+
+
+}