jnix

此软件包提供高级扩展，以帮助在 Rust 代码中使用 JNI。内部，它使用 jni-rs 软件包进行低级 JNI 操作。

提供一些辅助特质，例如

• AsJValue：允许 JNI 类型转换为 JValue 包装类型。
• IntoJava：允许 Rust 类型转换为 Java 类型。
• FromJava：允许 Rust 类型从 Java 类型创建。

还提供了一个辅助类型 JnixEnv，它是一个 JNIEnv 包装器，包含预加载类的内部类缓存。

如果使用 derive 功能标志编译，该软件包还导出过程宏到 derive IntoJava 和到 derive FromJava，这使得编写转换代码变得容易得多。例如：

use jnix::{
    jni::{objects::JObject, JNIEnv},
    JnixEnv, FromJava, IntoJava,
};

// Rust type definition
#[derive(Default, FromJava, IntoJava)]
#[jnix(package = "my.package")]
pub struct MyData {
    number: i32,
    string: String,
}

// A JNI function called from Java that creates a `MyData` Rust type, converts it to a Java
// type and returns it.
#[no_mangle]
#[allow(non_snake_case)]
pub extern "system" fn Java_my_package_JniClass_getData<'env>(
    env: JNIEnv<'env>,
    _this: JObject<'env>,
    data: JObject<'env>,
) -> JObject<'env> {
    // Create the `JnixEnv` wrapper
    let env = JnixEnv::from(env);

    // Convert parameter to Rust type
    let data = MyData::from_java(&env, data);

    // Create a new `MyData` object by converting from the Rust type. Since a smart pointer is
    // returned from `into_java`, the inner object must be "leaked" sothat the garbage collector
    // can own it afterwards
    data.into_java(&env).forget()
}

package my.package;

public class MyData {
    public MyData(int number, String string) {
        // This is the constructor that is called by the generated `IntoJava` code
        //
        // Note that the fields don't actually have to exist, the only thing that's necessary
        // is for the target Java class to have a constructor with the expected type signature
        // following the field order of the Rust type.
    }

    // These getters are called by the generated `FromJava` code
    public int getNumber() {
        return 10;
    }

    public String getString() {
        return "string value";
    }
}

许可证：Apache-2.0 OR MIT