值提取系列

字符串值提取工具-01-概览

字符串值提取工具-02-java 调用 js

字符串值提取工具-03-java 调用 groovy

字符串值提取工具-04-java 调用 java? Janino 编译工具

字符串值提取工具-05-java 调用 shell

字符串值提取工具-06-java 调用 python

字符串值提取工具-07-java 调用 go

字符串值提取工具-08-java 通过 xml-path 解析 xml

字符串值提取工具-09-java 执行 json 解析, json-path

字符串值提取工具-10-java 执行表达式引擎

拓展阅读

如果你对 json-path 不是很熟悉，建议学习：

Json Path-另一种解析 json 的方式 jsonpath

场景

我们希望通过 java 执行 json-path 解析 json。

核心实现

package com.github.houbb.value.extraction.core.support.extraction;

import com.github.houbb.value.extraction.api.ValueExtractionContext;
import com.jayway.jsonpath.Configuration;
import com.jayway.jsonpath.JsonPath;
import com.jayway.jsonpath.Option;
import com.jayway.jsonpath.ReadContext;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

/**
 *
 * @since 0.6.0
 */
public class ValueExtractionJsonPath extends AbstractValueExtractionAdaptor {

    @Override
    protected ReadContext prepare(ValueExtractionContext context) {
        final String json = (String) context.getDataMap().get("json");

        // 避免多次解析
        Configuration configuration = Configuration.builder().options(Option.DEFAULT_PATH_LEAF_TO_NULL).build();
        return JsonPath.parse(json, configuration);
    }

    @Override
    protected Object evaluate(ReadContext prepareObject, String script, ValueExtractionContext context) {
        return prepareObject.read(script);
    }

}

测试例子

public void test() {
        String json = "{"store":{"book":[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}],"bicycle":{"color":"red","price":19.95}},"expensive":10}";

        // 测试 getValueByXPath 方法
        String script = "$.store.book[1].author";

        // 创建绑定并设置参数
        Map bindings = new HashMap();
        bindings.put("json", json);

        String result = ValueExtractionBs.newInstance()
                .scripts(Arrays.asList(script))
                .valueExtraction(ValueExtractions.jsonPath())
                .dataMap(bindings)
                .extract().toString();

        Assert.assertEquals("{$.store.book[1].author=Evelyn Waugh}", result);
    }