Refactor Java API (#806)

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/WaveReader.java

@@ -0,0 +1,29 @@
+// Copyright 2024 Xiaomi Corporation
+package com.k2fsa.sherpa.onnx;
+
+public class WaveReader {
+    static {
+        System.loadLibrary("sherpa-onnx-jni");
+    }
+
+    private final int sampleRate;
+    private final float[] samples;
+
+    // It supports only single channel, 16-bit wave file.
+    // It will exit the program if the given file has a wrong format
+    public WaveReader(String filename) {
+        Object[] arr = readWaveFromFile(filename);
+        samples = (float[]) arr[0];
+        sampleRate = (int) arr[1];
+    }
+
+    public int getSampleRate() {
+        return sampleRate;
+    }
+
+    public float[] getSamples() {
+        return samples;
+    }
+
+    private native Object[] readWaveFromFile(String filename);
+}