java调用pmml算法模型

==背景==

项目需要调用算法模型，用于优化工艺参数。

==思路==

根据团队不具备算法训练能力的特点，技术上采用“训练与使用分离”的策略，

即：模型训练寻找第三方渠道，将训练好的算法模型导出pmml文件，然后通过java调用模型文件。

==代码样例==

【准备模型】

找朋友要了了一个测试用模型文件。如下图的：模型case.mht

【python代码】

编写python代码，导出模型为pmml文件。

# 导入模块
from sklearn.datasets import load_iris
from sklearn2pmml.pipeline import PMMLPipeline
from sklearn2pmml import sklearn2pmml
from sklearn2pmml import make_pmml_pipeline
from sklearn.tree import DecisionTreeClassifier as DTC
from sklearn import tree

# 实例化
iris=load_iris()
X=iris.data
y=iris.target

# 创建模型管道
pipeline = PMMLPipeline([
 ("classifier", DTC(criterion = 'entropy' ,max_depth = 5, min_samples_leaf = 1,))
])
# 训练模型
pipeline.fit(X,y)
# 导出模型到 RandomForestClassifier_Iris.pmml ⽂件
sklearn2pmml(pipeline, "iris_test.pmml")

【编写java代码】

1. pom文件

<dependency>
    <groupId>org.jpmml</groupId>
    <artifactId>pmml-evaluator</artifactId>
    <version>1.4.1</version>
</dependency>
<dependency>
    <groupId>org.jpmml</groupId>
    <artifactId>pmml-evaluator-extension</artifactId>
    <version>1.4.1</version>
</dependency>

2、java代码

package Pmml;

import org.dmg.pmml.FieldName;
import org.dmg.pmml.PMML;
import org.jpmml.evaluator.*;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * 算法模型测试
 * @author Chunhui.Qu
 */
public class PmmlTest {
    public static void main(String[] args) throws Exception {
        // 模型路径
        String path = "D:\\work\\06_WorkFile\\蓝格赛\\机器学习\\iris_test_4_3.pmml";

        // 传入模型特征数据
        Map<String, Double> map1 = new HashMap<>();
        map1.put("x1", 5.1);
        map1.put("x2", 3.5);
        map1.put("x3", 0.4);
        map1.put("x4", 0.2);

        // 模型预测
        predictLrHeart(map1, path);
    }

    public static void predictLrHeart(Map<String, Double> irismap, String path) throws Exception {
        File file = new File(path);
        try (InputStream is = new FileInputStream(file)) {
            PMML pmml = org.jpmml.model.PMMLUtil.unmarshal(is);

            ModelEvaluatorFactory modelEvaluatorFactory = ModelEvaluatorFactory.newInstance();
            ModelEvaluator<?> modelEvaluator = modelEvaluatorFactory.newModelEvaluator(pmml);

            List<InputField> inputFields = ((Evaluator) modelEvaluator).getInputFields();
            Map<FieldName, FieldValue> argements = new LinkedHashMap<>();
            for (InputField inputField : inputFields) {
                FieldName inputFieldName = inputField.getName();
                Object raeValue = irismap.get(inputFieldName.getValue());
                FieldValue inputFieldValue = inputField.prepare(raeValue);
                argements.put(inputFieldName, inputFieldValue);
            }
            Map<FieldName, ?> results = ((Evaluator) modelEvaluator).evaluate(argements);
            List<TargetField> targetFields = ((Evaluator) modelEvaluator).getTargetFields();
            for (TargetField targetField : targetFields) {
                FieldName targetFieldName = targetField.getName();
                Object targetFieldValue = results.get(targetFieldName);
                System.out.println(targetFieldValue);
            }
        }
    }
}

【运行结果】

==踩坑一个==

java代码执行可能会遇到如下异常：

Exception in thread "main" java.lang.IllegalArgumentException: http://www.dmg.org/PMML-4_4
    at org.dmg.pmml.Version.forNamespaceURI(Version.java:62)
    at org.jpmml.model.filters.PMMLFilter.updateSource(PMMLFilter.java:121)
    at org.jpmml.model.filters.PMMLFilter.startPrefixMapping(PMMLFilter.java:43)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startNamespaceMapping(AbstractSAXParser.java:2169)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:470)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:375)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:614)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3134)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:867)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:113)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:507)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:867)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:796)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:142)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1216)
    at org.xml.sax.helpers.XMLFilterImpl.parse(XMLFilterImpl.java:357)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:243)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:214)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:140)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:123)
    at org.jpmml.model.JAXBUtil.unmarshal(JAXBUtil.java:82)
    at org.jpmml.model.JAXBUtil.unmarshalPMML(JAXBUtil.java:68)
    at org.jpmml.model.PMMLUtil.unmarshal(PMMLUtil.java:35)
    at Pmml.PmmlTest.predictLrHeart(PmmlTest.java:38)
    at Pmml.PmmlTest.main(PmmlTest.java:32)