List<Float>转float[] List<Double>转double[]

1. 添加pom

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
</dependency>

2. List<Float>转float[] 

List<Float> feature = (List<Float>) jr.get("features");
float[] floatArray = ArrayUtils.toPrimitive(feature.toArray(new Float[0]), 0.0F);

3. List<Double>转double[]

List<Double> yList = new ArrayList<Double>();
Double[] dx = xList.toArray(new Double[xList.size()]);
double[] xArray = (double[]) ArrayUtils.toPrimitive(dx);