flink程序本地运行报： A JNI error has occurred和java.lang.NoClassDefFoundError

1.问题描述

在idea中运行flink job程序出现如下错误：

Error: A JNI error has occurred, please check your installation and try again

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/flink/api/common/io/FileInputFormat

at java.lang.Class.getDeclaredMethods0(Native Method)

at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)

at java.lang.Class.privateGetMethodRecursive(Class.java:3048)

at java.lang.Class.getMethod0(Class.java:3018)

at java.lang.Class.getMethod(Class.java:1784)

at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:650)

at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:632)

Caused by: java.lang.ClassNotFoundException: org.apache.flink.api.common.io.FileInputFormat

at java.net.URLClassLoader.findClass(URLClassLoader.java:387)

at java.lang.ClassLoader.loadClass(ClassLoader.java:418)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)

at java.lang.ClassLoader.loadClass(ClassLoader.java:351)

... 7 more

2.问题分析

2.1代码问题分析

java 复制代码

package test;

import org.apache.flink.api.java.io.TextInputFormat;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

/**
 * @Description
 * @Author 
 * @Date 2024/5/23
 * @Version 1.0
 */
public class ReadTextDemo {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        TextInputFormat textInputFormat = new TextInputFormat(null);
        DataStreamSource<String> source = env.readFile(textInputFormat, "D:\\datatest\\readtext.txt");
        source.print();
        env.execute("readText test");
    }
}

代码编译没有问题，但是却报类无法加载的异常，而且报错信息出现A JNI error has occurred，因此，猜测大概率和JDK有关，网上查了下解决方案：解决Java编译时错误:A JNI error has occurred,please check your installation and try again_java_脚本之家

但是通过验证，本地的JDK环境配置没有问题：

因此排除JDK问题的猜想。

2.2 pom配置问题分析

类无法正常加载还一种可能是pom依赖出现了问题，pom配置如下：

XML 复制代码

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>xxx-flink</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <flink.version>1.15.0</flink.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java</artifactId>
            <version>${flink.version}</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients</artifactId>
            <version>${flink.version}</version>
            <scope>provided</scope>
        </dependency>

        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <!--<groupId>org.apache.maven.plugins</groupId>-->
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <artifactId>maven-assembly-plugin </artifactId>
                <configuration>
                    <descriptorRefs>
                        <!-- 此处填写打包后jar包后添加的标识 -->
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <!-- 此处填写程序的主入口(main方法) -->
                            <mainClass>cn.xxx.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

对pom内容进行分析，发现flink jar依赖多了一行：

**<scope>provided</scope>**表示为当前依赖在打包过程中，不需要打进去，需要由运行的环境来提供，因此怀疑是它导致的，然后就将它注解掉，再次运行，发现程序正常执行。