# rust_java_samples

**Repository Path**: hellyguo/rust_java_samples

## Basic Information

- **Project Name**: rust_java_samples
- **Description**: rust-java 样例
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 1
- **Created**: 2024-07-15
- **Last Updated**: 2024-07-29

## Categories & Tags

**Categories**: Uncategorized

**Tags**: sample, demo, Rust, Java

## README

# rust-java samples

[Chinese version, 中文版](README_cn.md)

## desc

This repository contains sample `Rust` programs that call `Java` methods, and `Java` classes that call `Rust` methods.

## sample list

0. **sample000**, call `Rust` method from `Java`

   - [s000_hello.rs](sample/src/samples/s000_hello.rs)
   - [HelloWorld.java](sample4j/src/main/java/sample/s000/HelloWorld.java)

1. **sample001**, convert `Java` primitive types to bytes in `Rust`

   - [s001_bytes.rs](sample/src/samples/s001_bytes.rs)
   - [Bytes.java](sample4j/src/main/java/sample/s001/Bytes.java)

2. **sample002**, accept a `Java` object in `Rust`, and callback to `Java`

   - [s002_callback.rs](sample/src/samples/s002_callback.rs)
   - [Caller.java](sample4j/src/main/java/sample/s002/Caller.java)
   - [s002_callback_fast.rs](sample/src/samples/s002_callback_fast.rs)
   - [Caller2.java](sample4j/src/main/java/sample/s002/Caller2.java)

3. **sample003**, reverse `Java` bytes

   - [s003_reverse_bytes.rs](sample/src/samples/s003_reverse_bytes.rs)
   - [ReverseBytes.java](sample4j/src/main/java/sample/s003/ReverseBytes.java)

4. **sample004**, access `Java` DirectBuffer in `Rust`

   - [s004_direct_buf.rs](sample/src/samples/s004_direct_buf.rs)
   - [DirectBuf.java](sample4j/src/main/java/sample/s004/DirectBuf.java)

5. **sample005**, access `Java` primitive array in `Rust`

   - [s005_primitive_array.rs](sample/src/samples/s005_primitive_array.rs)
   - [PrimitiveArray.java](sample4j/src/main/java/sample/s005/PrimitiveArray.java)

6. **sample006**, create `Java` object in `Rust`

   - [s006_create_object.rs](sample/src/samples/s006_create_object.rs)
   - [ObjectCreator.java](sample4j/src/main/java/sample/s006/ObjectCreator.java)

7. **sample007**, set a field to `Java` object in `Rust`

   - [s007_fill_field.rs](sample/src/samples/s007_fill_field.rs)
   - [FieldFiller.java](sample4j/src/main/java/sample/s007/FieldFiller.java)

8. **sample008**, load `Java` class in `Rust`

   - [s008_load_class.rs](sample/src/samples/s008_load_class.rs)
   - [s008_class_buf.rs](sample/src/samples/s008_class_buf.rs)
   - [MemClassLoader.java](sample4j/src/main/java/sample/s008/MemClassLoader.java)

   > `s008_class_buf.rs` is generated by [java2u8vec.sh](shell/java2u8vec.sh)

9. **sample009**, register `Java` method dynamically in `Rust`

   - [s009_reg_method.rs](sample/src/samples/s009_reg_method.rs)
   - [NativeMethodRegister.java](sample4j/src/main/java/sample/s009/NativeMethodRegister.java)

[more ..](doc/sample_list.md)

## build

```shell
cargo build --release
```

`cargo` will generate `.so` in `target/release`, and call `build_java.sh` to build `.jar`, which contains `.so` in `resources` folder.

## how-to

1. call `Java` each JUnit test in IDE
2. call `Java` JUnit test suite in IDE

> **Note**: need to setup `JVM` args: `-DsampleLib=<path to lib>`

or

1. execute `Java` each JUnit test in console

    ```shell
    gradle test --tests HelloWorldTest
    ```

2. execute `Java` each JUnit test suite in console

    ```shell
    gradle test --tests SamplesSuite
    ```

The [JUnit report](sample4j/build/reports/tests/test/index.html) will be generated.

## thanks

Thanks to [metaworm](https://github.com/metaworm)([rust-java-demo](https://github.com/metaworm/rust-java-demo)). This article ([url1](https://zhuanlan.zhihu.com/p/568062165)/[url2](https://rustcc.cn/article?id=4ca84a67-d972-4460-912e-a297ec5edc0a)) is the most effective and detailed for learning how to call `JNI` through `Rust`.