java中[i=i++]问题

发表于 更新于 分类于 Waline： 阅读次数： 
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package tech.mapan;

public class add {
    public static void main(String[] args) {
        int i = 10;
        i = i++;
        System.out.println(i);
    }
}

输出结果为10，反编译结果

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Compiled from "add.java"
public class tech.mapan.add {
  public tech.mapan.add();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public static void main(java.lang.String[]);
    Code:
       0: bipush        10
       2: istore_1
       3: iload_1
       4: iinc          1, 1
       7: istore_1
       8: getstatic     #2                  // Field java/lang/System.out:Ljava/io/PrintStream;
      11: iload_1
      12: invokevirtual #3                  // Method java/io/PrintStream.println:(I)V
      15: return
}
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package tech.mapan;

public class add {
    public static void main(String[] args) {
        int i = 10;
        i = ++i;
        System.out.println(i);
    }
}

输出结果为11，反编译结果

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Compiled from "add.java"
public class tech.mapan.add {
  public tech.mapan.add();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public static void main(java.lang.String[]);
    Code:
       0: bipush        10
       2: istore_1
       3: iinc          1, 1
       6: iload_1
       7: istore_1
       8: getstatic     #2                  // Field java/lang/System.out:Ljava/io/PrintStream;
      11: iload_1
      12: invokevirtual #3                  // Method java/io/PrintStream.println:(I)V
      15: return
}