maven - 没有这样的字段错误: RESOURCE_PREFIX with a maven project using tess4j

Question

tess4j是一个包含原生库的OCR，我做了一个maven项目来测试它， 我确实将maven的安装路径添加到了eclipse中。 我添加了 M2_HOME、MAVEN_HOME 和 JAVA_HOME 环境变量，

这是我的父 pom

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                             http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>fr.mssb.ongoing</groupId>
    <artifactId>ongoing-parent</artifactId>
    <packaging>pom</packaging>
    <version>1.0</version>
    <name>ongoing</name>

    <modules>
        <module>capcha-solver</module>
    </modules>

    <build>
        <pluginManagement>
            <plugins>
                <!-- All project will be interpreted (source) and compiled (target) in java 7 -->
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.7</source>
                        <target>1.7</target>
                    </configuration>
                </plugin>
                <!-- this will make eclipse:eclipse goal work and make the project Eclipse compatible -->
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-eclipse-plugin</artifactId>
                    <version>2.5.1</version>
                    <configuration>
                        <downloadSources>true</downloadSources>
                        <downloadJavadocs>true</downloadJavadocs>
                        <classpathContainers>
                            <classpathContainer>org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.7</classpathContainer>
                        </classpathContainers>
                        <additionalBuildcommands>
                            <buildcommand>net.sf.eclipsecs.core.CheckstyleBuilder</buildcommand>
                        </additionalBuildcommands>
                        <additionalProjectnatures>
                            <projectnature>net.sf.eclipsecs.core.CheckstyleNature</projectnature>
                        </additionalProjectnatures>
                    </configuration>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>

    <!-- All child pom will inherit those dependancies -->
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

这是我的 child pom

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                             http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>fr.mssb.ongoing</groupId>
        <artifactId>ongoing-parent</artifactId>
        <version>1.0</version>
    </parent>

    <groupId>fr.mssb.ongoing</groupId>
    <artifactId>capcha-solver</artifactId>
    <version>1.0</version>
    <packaging>jar</packaging> <!-- I think this is useless -->

    <name>A capcha solver based on terassec ocr</name>

    <build>
        <plugins>
            <!-- autorun unit tests during maven compilation -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <argLine>-Xmx1024m -XX:MaxPermSize=256m -XX:-UseSplitVerifier</argLine>
                    <skipTests>-DskipTests</skipTests>
                </configuration>
            </plugin>

            <!--  this should make the tesseract ocr native dll work without doing anything -->
            <plugin>
                <groupId>com.googlecode.mavennatives</groupId>
                <artifactId>maven-nativedependencies-plugin</artifactId>
                <version>0.0.7</version>
                <executions>
                    <execution>
                        <id>unpacknatives</id>
                        <goals>
                            <goal>copy</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <!-- 
        Log4j 2 is broken up in an API and an implementation (core), where the API 
        provides the interface that applications should code to. Strictly speaking 
        Log4j core is only needed at runtime and not at compile time.
        However, below we list Log4j core as a compile time dependency to improve 
        the startup time for custom plugins. 
        -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.1</version>
        </dependency>
        <!--
        Integration of tesseract OCR
        -->
        <dependency>
            <groupId>net.sourceforge.tess4j</groupId>
            <artifactId>tess4j</artifactId>
            <version>1.4.1</version>
        </dependency>
    </dependencies>

</project>

当然还有代码(取自 tess4j 示例)

package test;

import java.io.File;

import net.sourceforge.tess4j.Tesseract;
import net.sourceforge.tess4j.TesseractException;

/**
 * Classe d'exemple.
 */
public class TesseractExample {

    public static void main(String[] args) {
        File imageFile = new File("C:\\DEV\\repo\\ongoing\\capcha-solver\\src\\test\\resources\\random.jpg");
        Tesseract instance = Tesseract.getInstance();  // JNA Interface Mapping
        // Tesseract1 instance = new Tesseract1(); // JNA Direct Mapping

        try {
            String result = instance.doOCR(imageFile);
            System.out.println(result);
        } catch (TesseractException e) {
            System.err.println(e.getMessage());
        }
    }
}

当我启动它时，我遇到了这个异常

Exception in thread "main" java.lang.NoSuchFieldError: RESOURCE_PREFIX
    at net.sourceforge.tess4j.util.LoadLibs.<clinit>(LoadLibs.java:60)
    at net.sourceforge.tess4j.TessAPI.<clinit>(TessAPI.java:40)
    at net.sourceforge.tess4j.Tesseract.init(Tesseract.java:303)
    at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:239)
    at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:188)
    at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:172)
    at test.TesseractExample.main(TesseractExample.java:19)

我不知道这是否与 tess4j 相关或 JNA/JNI 问题，正如你所看到的，我有一个插件“应该”(以前从未使用过 DLL)让它们工作。

另外，在父pom中，我的插件位于插件管理标签之间，我想我应该将它们放在构建标签之间，不是吗？

有什么想法吗？

谢谢。

Answer 1

有 2 个问题

1/tess4j 中的一些 dll 和文件必须复制到项目根目录

2/tess4j 对 com.sun.jna:jna:jar:3.0.9 具有传递依赖性，与 net.java.dev.jna:jna:jar:4.1.0(也来自 tess4j)冲突，包括 3.0。 9 版本使一切正常，RESSOURCE_PREFIX 错误来自于此

32 位版本的 pom.xml(您需要安装 32 位 JVM)，它负责这两件事，如果您想在 64 位中使用它，请将 win32-x86 更改为 win32-x86-64

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                             http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>fr.mssb.ocr</groupId>
    <artifactId>tesseractOcr</artifactId>
    <version>1.0</version>
    <packaging>jar</packaging>

    <name>tesseract ocr project</name>

    <build>
        <plugins>
            <!--  
            this extract the 32 bits dll and the tesseractdata folder to 
            the project root from tess4j.jar  
            -->
            <plugin>
                <groupId>org.apache.portals.jetspeed-2</groupId>
                <artifactId>jetspeed-unpack-maven-plugin</artifactId>
                <version>2.2.2</version>
                <dependencies>
                    <dependency>
                      <groupId>net.sourceforge.tess4j</groupId>
                      <artifactId>tess4j</artifactId>
                      <version>1.4.1</version>
                    </dependency>
                </dependencies>
                <executions>
                    <execution>
                        <id>unpack-step</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>unpack</goal>
                        </goals>
                        <configuration>
                            <unpack>
                                <artifact>net.sourceforge.tess4j:tess4j:jar</artifact>
                                <overwrite>true</overwrite>
                                <resources combine.children="append">
                                    <resource>
                                        <path>win32-x86</path>
                                        <destination>../</destination>
                                        <overwrite>true</overwrite>
                                        <flat>true</flat>
                                        <include>*</include>
                                    </resource>
                                    <resource>
                                        <path>tessdata</path>
                                        <destination>../tessdata</destination>
                                        <overwrite>true</overwrite>
                                        <flat>true</flat>
                                        <include>*</include>
                                    </resource>
                                    <resource>
                                        <path>tessdata/configs</path>
                                        <destination>../tessdata/configs</destination>
                                        <overwrite>true</overwrite>
                                        <flat>true</flat>
                                        <include>*</include>
                                    </resource>
                                </resources>
                            </unpack>
                            <verbose>true</verbose>
                        </configuration>
                        </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>net.sourceforge.tess4j</groupId>
            <artifactId>tess4j</artifactId>
            <version>1.4.1</version>
              <exclusions>
                <exclusion>
                    <groupId>com.sun.jna</groupId>
                    <artifactId>jna</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

</project>