java - Jackson lib gradle 的 Eclipse 类路径问题

Question

我的项目在 eclipseoxy 和 mars 中打开一次，我看到了在 eclipseoxy 中导入 jackson lib 的修复(eclipse 建议) - 我这样做了，它解决了那里的问题 - 尽管我已经提到了相同的依赖项在我的项目的 gradle 依赖项列表中。

之后，我在 eclipse mars 中打开了相同的项目，并且依赖项显示在我的 gradle deps 列表中的 buildpath(eclipse list of deps) 中，但 eclipse mars 仍然在源代码上显示错误。

我清理了项目并做了 ./gradlew eclipse - 一切都很成功，但 eclipse mars 无法解决依赖关系 - 我应该如何解决这个问题。

我的build.gradle是

/*
 * This build file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java Library project to get you started.
 * For more details take a look at the Java Libraries chapter in the Gradle
 * user guide available at https://docs.gradle.org/3.5/userguide/java_library_plugin.html
 */

// Apply the java-library plugin to add support for Java Library
apply plugin: 'java-library'
apply plugin: 'eclipse'

// In this section you declare where to find the dependencies of your project
repositories {
    // Use jcenter for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
    mavenCentral()
}

dependencies {
    // This dependency is exported to consumers, that is to say found on their compile classpath.
    api 'org.apache.commons:commons-math3:3.6.1'

    // This dependency is used internally, and not exposed to consumers on their own compile classpath.
    implementation 'com.google.guava:guava:21.0'

    // Use JUnit test framework
    testImplementation 'junit:junit:4.12'

    // https://mvnrepository.com/artifact/org.jsoup/jsoup
    compile group: 'org.jsoup', name: 'jsoup', version: '1.11.2'

    // https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core
    compile group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: '2.9.3'


}

这是我的引用代码

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Iterator;
import java.util.Scanner;
import java.util.regex.Pattern;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;

public class Main {

//  public ObjectMapper mapper = new ObjectMapper();

    public static void main(String[] args) {
//      for (String html : args) {
//          Main main = new Main();
//          try {
//              main.parseHtml(html);
//          } catch (JsonProcessingException e) {
//              e.printStackTrace();
//          }
//      }

        Main main = new Main();

        String html = main.getFile("appleInc.html");
        try {
            main.parseHtml(html);
        } catch (JsonProcessingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private String getFile(String fileName) {

        StringBuilder result = new StringBuilder("");

        //Get file from resources folder
        ClassLoader classLoader = getClass().getClassLoader();
        File file = new File(classLoader.getResource(fileName).getFile());

        try (Scanner scanner = new Scanner(file)) {

            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                result.append(line).append("\n");
            }

            scanner.close();

        } catch (IOException e) {
            e.printStackTrace();
        }

        return result.toString();

      }

    public void parseHtml(String html) throws JsonProcessingException {
        Document document = Jsoup.parse(html);
        // parse all the table required
//      ArrayNode tableInfo = retrieveTableInfo(document);

        // get the metadata from the html
        ObjectNode metadataObject = retrieveMetadataInfo(document);
//      tableInfo.add(metadataObject);
//      System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(tableInfo));
    }

    @SuppressWarnings("unused")
    private ObjectNode retrieveMetadataInfo(Document document) {
        String type = document.getElementsByTag("type").text();
        String companyName = findCompanyName(document);
        String employerIdentificationNo = findEmployerIdentificationNumber(document);
        return null;
    }

    private String findEmployerIdentificationNumber(Document document) {
        String employerNo = "";
        employerNo = document.getElementsContainingText("I.R.S. Employer").prev("div").text();
        if (employerNo.isEmpty()) {
            Iterator<Element> iterator = document.getElementsContainingText("Employer Identification").prev("tr")
                    .iterator();
            while (iterator.hasNext()) {
                Element element = (Element) iterator.next();
                if (element.is("tr")) {
                    employerNo = element.getElementsMatchingText(getPattern()).text();
                }
            }
        }
        return null;
    }

    private Pattern getPattern() {
        String re1 = "(\\d+)";
        String re2 = "(-)";
        String re3 = "(\\d+)";

        return Pattern.compile(re1 + re2 + re3, Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
    }

    private String findCompanyName(Document document) {
        return document.getElementsContainingText("Exact name of Registrant").prev("div").text();
    }

    private ArrayNode retrieveTableInfo(Document document) {
        Elements tables = document.getElementsByTag("table");
        tables.forEach(table -> {
            if (Validator.isTableUsefull(table))
                return;
            String tableTitle = getTableTitle(document, table);

        });

        return null;
    }

    private String getTableTitle(Document document, Element table) {
        // TODO Auto-generated method stub
        return null;
    }
}

Answer 1

您使用的类不属于 jackson 核心。浏览the documentation可以看到，或者简单地通过查看 jar 文件的内容。

如您所见，来自包 com.fasterxml.jackson.core 的类 JsonProcessingException 被发现没有问题。那是因为它是 jackson-core 的一部分。

缺少的类都在com.fasterxml.jackson.databind包中。要解决这些问题，您需要添加所需的库:com.fasterxml.jackson.core:jackson-databind。