Class文件结构-常量池

常量池里存放：
1.字面量(literal)
• 文本字符串
• 声明为final的常量值(final的8种基本类型)
• 非final的基本类型也可能进(doublefloatlong)
2.符号引用(symbolic references)
• 类和接口的全限定名(fully qualified name)
• 字段的名称和描述符(descriptor)
• 方法的名称和描述符
备注：
1. constant_pool_count=1表示常量池中有0个常量项
2. 表的第一个字节表示常量类型(tag)

常量项结构总表

 示例：

package zero.desk.constantpool;

public class constantpool extends c implements a,b{
    private string str = "test string";
    private final int a = 10;
    private final long b = 10;
    private final long bb = 100;
    private int c = 11;
    private float d = 12f;
    private float e = 12f;
    private double ee = 12f;

    private int m;

    public int inc() {
        return m + 1;
    }
}

constant pool:
#1 = methodref #20.#50 // zero/desk/constantpool/c."<init>":()v
#2 = string #51 // test string
#3 = fieldref #19.#52 // zero/desk/constantpool/constantpool.str:ljava/lang/string;
#4 = fieldref #19.#53 // zero/desk/constantpool/constantpool.a:i
#5 = long 10l
#7 = fieldref #19.#54 // zero/desk/constantpool/constantpool.b:j
#8 = long 100l
#10 = fieldref #19.#55 // zero/desk/constantpool/constantpool.bb:j
#11 = fieldref #19.#56 // zero/desk/constantpool/constantpool.c:i
#12 = float 12.0f
#13 = fieldref #19.#57 // zero/desk/constantpool/constantpool.d:f
#14 = fieldref #19.#58 // zero/desk/constantpool/constantpool.e:f
#15 = double 12.0d
#17 = fieldref #19.#59 // zero/desk/constantpool/constantpool.ee:d
#18 = fieldref #19.#60 // zero/desk/constantpool/constantpool.m:i
#19 = class #61 // zero/desk/constantpool/constantpool
#20 = class #62 // zero/desk/constantpool/c
#21 = class #63 // zero/desk/constantpool/a
#22 = class #64 // zero/desk/constantpool/b
#23 = utf8 str
#24 = utf8 ljava/lang/string;
#25 = utf8 a
#26 = utf8 i
#27 = utf8 constantvalue
#28 = integer 10
#29 = utf8 b
#30 = utf8 j
#31 = utf8 bb
#32 = utf8 c
#33 = utf8 d
#34 = utf8 f
#35 = utf8 e
#36 = utf8 ee
#37 = utf8 d
#38 = utf8 m
#39 = utf8 <init>
#40 = utf8 ()v
#41 = utf8 code
#42 = utf8 linenumbertable
#43 = utf8 localvariabletable
#44 = utf8 this
#45 = utf8 lzero/desk/constantpool/constantpool;
#46 = utf8 inc
#47 = utf8 ()i
#48 = utf8 sourcefile
#49 = utf8 constantpool.java
#50 = nameandtype #39:#40 // "<init>":()v
#51 = utf8 test string
#52 = nameandtype #23:#24 // str:ljava/lang/string;
#53 = nameandtype #25:#26 // a:i
#54 = nameandtype #29:#30 // b:j
#55 = nameandtype #31:#30 // bb:j
#56 = nameandtype #32:#26 // c:i
#57 = nameandtype #33:#34 // d:f
#58 = nameandtype #35:#34 // e:f
#59 = nameandtype #36:#37 // ee:d
#60 = nameandtype #38:#26 // m:i
#61 = utf8 zero/desk/constantpool/constantpool
#62 = utf8 zero/desk/constantpool/c
#63 = utf8 zero/desk/constantpool/a
#64 = utf8 zero/desk/constantpool/b