java8-注释比较<；T>；具有可比性<；T>；将注释添加到compareTo（对象o）
我有一个注解java8-注释比较<；T>；具有可比性<；T>；将注释添加到compareTo（对象o）,java,annotations,java-8,Java,Annotations,Java 8,我有一个注解 package javaannotationtest; import java.lang.annotation.*; @Target({ElementType.METHOD}) @Retention(RetentionPolicy.RUNTIME) public @interface CustomAnnotation { } 这将应用于以下类中的compareTo package javaannotationtest; public class Customer imple
package javaannotationtest;
import java.lang.annotation.*;
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface CustomAnnotation {
}
package javaannotationtest;
public class Customer implements Comparable<Customer>{
@Override
@CustomAnnotation
public int compareTo(Customer o) {
return 0;
}
}
1.8.0 -> public int javaannotationtest.Customer.compareTo(javaannotationtest.Customer)
has annotation of type javaannotationtest.CustomAnnotation
1.8.0 -> public int javaannotationtest.Customer.compareTo(java.lang.Object)
has annotation of type javaannotationtest.CustomAnnotation
compareTo（Java.lang.Object）Classfile/C:/code/java8annoation/out/production/java8annoation/javaannoationtest/Customer.class
最后修改日期：2014年4月17日；大小719字节
MD5校验和678e0371f5f9ed5666b513c940f365a7
从“Customer.java”编译而来
公共类javaannotationtest.Customer扩展了java.lang.Object实现了java.lang.Test
签名：#20//Ljava/lang/Object；Ljava/lang/Comparable；
源文件：“Customer.java”
次要版本：0
主要版本：52
旗帜：ACC_公共、ACC_超级
固定池：
#1=Methodref#4.#23//java/lang/Object.“：（）V
#2=类#24//javaannotationtest/客户
#3=Methodref#2.#25//javaannotationtest/Customer.compareTo:（Ljavaannotationtest/Customer；）I
#4=类#26//java/lang/Object
#5=类#27//java/lang/Comparable
#6=Utf8
#7=Utf8（）V
#8=Utf8代码
#9=Utf8行号表
#10=Utf8 LocalVariableTable
#11=Utf8此
#12=Utf8 Ljavaannotationtest/客户；
#13=Utf8比较到
#14=Utf8（Ljavaannotationtest/Customer；）I
#15=Utf8 o
#16=Utf8运行时访问说明
#17=Utf8 Ljavaannotationtest/CustomAnnotation；
#18=Utf8（Ljava/lang/Object；）I
#19=Utf8签名
#20=Utf8 Ljava/lang/Object；Ljava/lang/Comparable；
#21=Utf8源文件
#22=Utf8 Customer.java
#23=名称和类型#6:#7/“”：（）V
#24=Utf8 javaannotationtest/客户
#25=名称和类型#13:#14//比较到：（Ljavaannotationtest/Customer；）I
#26=Utf8 java/lang/Object
#27=Utf8 java/lang/Compariable
{
public javaannotationtest.Customer（）；
描述符：（）V
旗帜：ACC_PUBLIC
代码：
堆栈=1，局部变量=1，参数大小=1
0:aload_0
1:invokespecial#1//方法java/lang/Object。“：（）V
4：返回
LineNumberTable：
第3行：0
LocalVariableTable：
起始长度插槽名称签名
0 5 0此Ljavaannotationtest/客户；
public int compareTo（javaannotationtest.Customer）；
描述符：（Ljavaannotationtest/Customer；）I
旗帜：ACC_PUBLIC
代码：
堆栈=1，局部变量=2，参数大小=2
0:iconst_0
1:我轮到你了
LineNumberTable：
第7行：0
LocalVariableTable：
起始长度插槽名称签名
0 2 0此Ljavaannotationtest/客户；
0 2 1 o Ljavaannotationtest/客户；
运行时访问说明：
0: #17()
public int compareTo（java.lang.Object）；
描述符：（Ljava/lang/Object；）I
标志：ACC_公共、ACC_桥、ACC_合成
代码：
堆栈=2，局部变量=2，参数大小=2
0:aload_0
1:aload_1
2:checkcast#2//class javaannotationtest/Customer
5:invokevirtual#3//方法比较：（Ljavaannotationtest/Customer；）I
8：我轮到你了
LineNumberTable：
第3行：0
LocalVariableTable：
起始长度插槽名称签名
0 9 0此Ljavaannotationtest/客户；
运行时访问说明：
0: #17()
}
有人能解释一下Java8中的相关变化吗？（在符合条件时将提供赏金）。本期中描述了这一变化。关于这个特性似乎没有太多的讨论，但是请求和理由对我来说是有意义的 请求的说明： 当一个类扩展了一个泛型类或实现了一个泛型接口时，由于擦除的原因，可能会生成一个合成方法，在采用特定参数/返回的方法和用对象定义的超类/接口之间架起桥梁。根据Java语言规范，桥接方法将调用重定向到实际方法。但是，桥接方法缺少为原始方法及其参数定义的注释 理由： 当试图在运行时检索此类方法的注释时，会出现问题。因为不可能可靠地找出哪些类替换了泛型参数，所以我们不知道要将哪个参数发送到getMethod（…）以接收正确的方法。当发送Object.class（而泛型参数是另一个类）时，getMethod将返回bridge方法，该方法将不包含有关原始方法注释的信息 还记录在以下文件中： 区域：工具/javac 简介
从本版本开始，参数和方法注释被复制到合成桥方法。此修复意味着现在对于以下程序：
@Target(value = {ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@interface ParamAnnotation {}
@Target(value = {ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@interface MethodAnnotation {}
abstract class T<A,B> {
B m(A a){return null;}
}
class CovariantReturnType extends T<Integer, Integer> {
@MethodAnnotation
Integer m(@ParamAnnotation Integer i) {
return i;
}
public class VisibilityChange extends CovariantReturnType {}
}
@Target（值={ElementType.PARAMETER}）
@保留（RetentionPolicy.RUNTIME）
@接口参数{}
@目标（值={ElementType.METHOD}）
@保留（RetentionPolicy.RUNTIME）
@接口方法注释{}
抽象类T
@卡普：回答得很好。我想补充一些关于这个问题的补充资料。不仅注释被复制到bridg
Classfile /C:/code/java8annoation/out/production/java8annoation/javaannotationtest/Customer.class
Last modified 17 Apr, 2014; size 719 bytes
MD5 checksum 678e0371f5f9ed5666b513c940f365a7
Compiled from "Customer.java"
public class javaannotationtest.Customer extends java.lang.Object implements java.lang.Comparable<javaannotationtest.Customer>
Signature: #20 // Ljava/lang/Object;Ljava/lang/Comparable<Ljavaannotationtest/Customer;>;
SourceFile: "Customer.java"
minor version: 0
major version: 52
flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
#1 = Methodref #4.#23 // java/lang/Object."<init>":()V
#2 = Class #24 // javaannotationtest/Customer
#3 = Methodref #2.#25 // javaannotationtest/Customer.compareTo:(Ljavaannotationtest/Customer;)I
#4 = Class #26 // java/lang/Object
#5 = Class #27 // java/lang/Comparable
#6 = Utf8 <init>
#7 = Utf8 ()V
#8 = Utf8 Code
#9 = Utf8 LineNumberTable
#10 = Utf8 LocalVariableTable
#11 = Utf8 this
#12 = Utf8 Ljavaannotationtest/Customer;
#13 = Utf8 compareTo
#14 = Utf8 (Ljavaannotationtest/Customer;)I
#15 = Utf8 o
#16 = Utf8 RuntimeVisibleAnnotations
#17 = Utf8 Ljavaannotationtest/CustomAnnotation;
#18 = Utf8 (Ljava/lang/Object;)I
#19 = Utf8 Signature
#20 = Utf8 Ljava/lang/Object;Ljava/lang/Comparable<Ljavaannotationtest/Customer;>;
#21 = Utf8 SourceFile
#22 = Utf8 Customer.java
#23 = NameAndType #6:#7 // "<init>":()V
#24 = Utf8 javaannotationtest/Customer
#25 = NameAndType #13:#14 // compareTo:(Ljavaannotationtest/Customer;)I
#26 = Utf8 java/lang/Object
#27 = Utf8 java/lang/Comparable
{
public javaannotationtest.Customer();
descriptor: ()V
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 3: 0
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Ljavaannotationtest/Customer;
public int compareTo(javaannotationtest.Customer);
descriptor: (Ljavaannotationtest/Customer;)I
flags: ACC_PUBLIC
Code:
stack=1, locals=2, args_size=2
0: iconst_0
1: ireturn
LineNumberTable:
line 7: 0
LocalVariableTable:
Start Length Slot Name Signature
0 2 0 this Ljavaannotationtest/Customer;
0 2 1 o Ljavaannotationtest/Customer;
RuntimeVisibleAnnotations:
0: #17()
public int compareTo(java.lang.Object);
descriptor: (Ljava/lang/Object;)I
flags: ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
Code:
stack=2, locals=2, args_size=2
0: aload_0
1: aload_1
2: checkcast #2 // class javaannotationtest/Customer
5: invokevirtual #3 // Method compareTo:(Ljavaannotationtest/Customer;)I
8: ireturn
LineNumberTable:
line 3: 0
LocalVariableTable:
Start Length Slot Name Signature
0 9 0 this Ljavaannotationtest/Customer;
RuntimeVisibleAnnotations:
0: #17()
}
@Target(value = {ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@interface ParamAnnotation {}
@Target(value = {ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@interface MethodAnnotation {}
abstract class T<A,B> {
B m(A a){return null;}
}
class CovariantReturnType extends T<Integer, Integer> {
@MethodAnnotation
Integer m(@ParamAnnotation Integer i) {
return i;
}
public class VisibilityChange extends CovariantReturnType {}
}
public int compareTo(Customer);
descriptor: (LCustomer;)I
flags: ACC_PUBLIC
Code:
stack=1, locals=2, args_size=2
0: iconst_0
1: ireturn
LineNumberTable:
line 11: 0
MethodParameters:
Name Flags
o
RuntimeVisibleAnnotations:
0: #15()
public int compareTo(java.lang.Object);
descriptor: (Ljava/lang/Object;)I
flags: ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
Code:
stack=2, locals=2, args_size=2
0: aload_0
1: aload_1
2: checkcast #2 // class Customer
5: invokevirtual #3 // Method compareTo:(LCustomer;)I
8: ireturn
LineNumberTable:
line 7: 0
MethodParameters:
Name Flags
o synthetic <-- see the name copied to the bridge method
RuntimeVisibleAnnotations:
0: #15()