求一下java for 循环 机器指令数

[iamsangster]

long num = 10000000000l;
long l = System.currentTimeMillis();
for (long j = 0 ; j < num; j++)
{
}

共多少机器指令,我的机子运行约10s; num 百亿

[lcllcl987]

用javap命令看一下不就ok？

[KingNE]

up

[codeartisan]

嫌javap麻烦的话，装一个bytecode插件就好咯。

[codeartisan]

源代码：
package action;
public class Test {
public static void main(String[] args) {
long num = 10000000000l;
long l = System.currentTimeMillis();
for (long j = 0; j < num; j++) {
System.out.println();
}
}
}

==========================================================================

虚拟机指令：

// class version 49.0 (49)
// access flags 33
public class action/Test {

// compiled from: Test.java

// access flags 1
public <init>()V
L0 (0)
LINENUMBER 2 L0
ALOAD 0
INVOKESPECIAL java/lang/Object.<init>()V
RETURN
L1 (4)
LOCALVARIABLE this Laction/Test; L0 L1 0
MAXSTACK = 1
MAXLOCALS = 1

// access flags 9
public static main([Ljava/lang/String;)V
L0 (0)
LINENUMBER 4 L0
LDC 10000000000
LSTORE 1
L1 (3)
LINENUMBER 5 L1
INVOKESTATIC java/lang/System.currentTimeMillis()J
LSTORE 3
L2 (6)
LINENUMBER 6 L2
LCONST_0
LSTORE 5
L3 (9)
GOTO L4
L5 (11)
LINENUMBER 7 L5
GETSTATIC java/lang/System.out : Ljava/io/PrintStream;
INVOKEVIRTUAL java/io/PrintStream.println()V
L6 (14)
LINENUMBER 6 L6
LLOAD 5
LCONST_1
LADD
LSTORE 5
L4 (19)
LLOAD 5
LLOAD 1
LCMP
IFLT L5
L7 (24)
LINENUMBER 9 L7
RETURN
L8 (26)
LOCALVARIABLE args [Ljava/lang/String; L0 L8 0
LOCALVARIABLE num J L1 L8 1
LOCALVARIABLE l J L2 L8 3
LOCALVARIABLE j J L3 L7 5
MAXSTACK = 4
MAXLOCALS = 7
}


====================================================================
嫌javap麻烦的话，装一个bytecode插件就好咯。

[iamsangster]

System.out.println(); 会死人的