关于Gen生成try-catch-finally

Posted 2020-12-27 extjs4

 

 

class TestExc extends Exception{}
void tryItOut () throws TestExc{}
void handleExc(Object o){}

void catchOne() {
	try {
		tryItOut();
	} catch (TestExc e) {
		handleExc(e);
	}
}

　　

 

public class com.test19.Test04
  SourceFile: "Test04.java"
  InnerClasses:
       #7= #3 of #5; //TestExc=class com/test19/Test04$TestExc of class com/test                                                                                                                19/Test04
  minor version: 0
  major version: 51
  flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
   #1 = Methodref          #6.#29         //  java/lang/Object."<init>":()V
   #2 = Methodref          #5.#30         //  com/test19/Test04.tryItOut:()V
   #3 = Class              #31            //  com/test19/Test04$TestExc
   #4 = Methodref          #5.#32         //  com/test19/Test04.handleExc:(Ljava                                                                                                                /lang/Object;)V
   #5 = Class              #33            //  com/test19/Test04
   #6 = Class              #34            //  java/lang/Object
   #7 = Utf8               TestExc
   #8 = Utf8               InnerClasses
   #9 = Utf8               <init>
  #10 = Utf8               ()V
  #11 = Utf8               Code
  #12 = Utf8               LineNumberTable
  #13 = Utf8               LocalVariableTable
  #14 = Utf8               this
  #15 = Utf8               Lcom/test19/Test04;
  #16 = Utf8               tryItOut
  #17 = Utf8               Exceptions
  #18 = Utf8               handleExc
  #19 = Utf8               (Ljava/lang/Object;)V
  #20 = Utf8               o
  #21 = Utf8               Ljava/lang/Object;
  #22 = Utf8               catchOne
  #23 = Utf8               e
  #24 = Utf8               Lcom/test19/Test04$TestExc;
  #25 = Utf8               StackMapTable
  #26 = Class              #31            //  com/test19/Test04$TestExc
  #27 = Utf8               SourceFile
  #28 = Utf8               Test04.java
  #29 = NameAndType        #9:#10         //  "<init>":()V
  #30 = NameAndType        #16:#10        //  tryItOut:()V
  #31 = Utf8               com/test19/Test04$TestExc
  #32 = NameAndType        #18:#19        //  handleExc:(Ljava/lang/Object;)V
  #33 = Utf8               com/test19/Test04
  #34 = Utf8               java/lang/Object
{
  public com.test19.Test04();
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokespecial #1                  // Method java/lang/Object."<init>                                                                                                                ":()V
         4: return
      LineNumberTable:
        line 2: 0
        line 20: 4
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               0       5     0  this   Lcom/test19/Test04;

  void tryItOut() throws com.test19.Test04$TestExc;
    flags:
    Code:
      stack=0, locals=1, args_size=1
         0: return
      LineNumberTable:
        line 21: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               0       1     0  this   Lcom/test19/Test04;
    Exceptions:
      throws com.test19.Test04$TestExc

  void handleExc(java.lang.Object);
    flags:
    Code:
      stack=0, locals=2, args_size=2
         0: return
      LineNumberTable:
        line 22: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               0       1     0  this   Lcom/test19/Test04;
               0       1     1     o   Ljava/lang/Object;

  void catchOne();
    flags:
    Code:
      stack=2, locals=2, args_size=1
         0: aload_0
         1: invokevirtual #2                  // Method tryItOut:()V
         4: goto          13
         7: astore_1
         8: aload_0
         9: aload_1
        10: invokevirtual #4                  // Method handleExc:(Ljava/lang/Ob                                                                                                                ject;)V
        13: return
      Exception table:
         from    to  target type
             0     4     7   Class com/test19/Test04$TestExc
      LineNumberTable:
        line 26: 0
        line 29: 4
        line 27: 7
        line 28: 8
        line 30: 13
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               8       5     1     e   Lcom/test19/Test04$TestExc;
               0      14     0  this   Lcom/test19/Test04;
      StackMapTable: number_of_entries = 2
           frame_type = 71 /* same_locals_1_stack_item */
          stack = [ class com/test19/Test04$TestExc ]
           frame_type = 5 /* same */

}

　　

 

 

 2A B6 00 02 A7 00 09 4C 2A 2B B6 00 04 B1

opcode [2A] - 0000: aload_0
opcode [B6] - 0001: invokevirtual 2 [Methodref: com.test19.Test04.tryItOut, parameter = (), returns = void]
opcode [A7] - 0004: goto 9
opcode [4C] - 0007: astore_1
opcode [2A] - 0008: aload_0
opcode [2B] - 0009: aload_1
opcode [B6] - 0010: invokevirtual 4 [Methodref: com.test19.Test04.handleExc, parameter = (java.lang.Object), returns = void]
opcode [B1] - 0013: return