JNI field descriptor "([Ljava/lang/String;) V"
"([Ljava/lang/String;) V" It is a coding of the return value and parameters of the function. This encoding is called JNI Field Descriptors (JavaNative Interface Field Descriptors). An array of int [] needs to be expressed as "[I". If multiple arrays double [] [] [] need to be expressed as "[[[D". In other words, the beginning of each square bracket means an array dimension. Behind multiple boxes is the type of array.
If the descriptor starts with an L, it is the class descriptor, which is followed by the string of the class, and then the semicolon ";" ends.
For example, "Ljava/lang/String;" means the type String;
"[I" means int [];
"[Ljava/lang/Object;" means Object [].
The JNI method descriptor is mainly to put the parameters in parentheses and the return type after the parentheses, as follows:
(Parameter descriptor) return type
When a function does not need to return the parameter type, it is represented by "V".
For example, "() Ljava/lang/String;" means String f ();
"(ILjava/lang/Class;) J" means long f (int i, Class c);
"([B) V" means void String (byte [] bytes);
| Java types | symbol |
|---|---|
| Boolean | Z |
| Byte | B |
| Char | C |
| Short | S |
| Int | I |
| Long | J |
| Float | F |
| Double | D |
| Void | V |
| objects | Start with "L" and end with ";", in the middle are the package and class names separated by "/". For example: Ljava/lang/String; if it is a nested class, use To Table shows the insert sleeve . Example The"(Ljava/lang/String;Landroid/os/FileUtils FileStatus;) Z " |
In addition, the abbreviation of the array type can be expressed by "[" plus the short form of the corresponding type shown in Table A,
For example: [I means int []; [L/java/lang/objects; means Objects [], in addition. Reference types (except for arrays of basic types) have a ";" at the end
E.g:
"() V" means void Func ();
"(II) V" means void Func (int, int);
"(Ljava/lang/String; Ljava/lang/String;) I". Means int Func (String, String)