【发布时间】：2015-08-04 14:10:04
【问题描述】：
tess4j 是一个包含原生库的 OCR，我做了一个 maven 项目来测试它， 我确实在eclipse中添加了maven的安装路径。 我添加了 M2_HOME、MAVEN_HOME 和 JAVA_HOME 环境变量，
这是我的父母 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>
这是我的孩子 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，我得到了这个异常
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，如您所见，我有一个插件“应该”（以前从未与 DLL 一起使用）使其工作。
同样在父 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。
【问题讨论】：
-
可能是 JNA 版本不匹配。尝试使用
-Djna.nosys=True运行以避免无意中选择了安装在系统上的（旧）版本的 JNA。 -
不，不会改变任何东西
-
RESOURCE_PREFIX是 JNA 常量。你安装了吗？ -
是的，我已经安装了 VS2013 visual c++ redistribuable，如下所示：tess4j.sourceforge.net/usage.html
-
你需要添加 jna 4.1.0 依赖。
标签： maven java-native-interface tesseract jna tess4j