No leveldbjni64-1.8 in Java.library.path

An issue was encountered while extracting the trie tree portion of the Ethereum Java version:

Exception in thread "main" java.lang.UnsatisfiedLinkError: Could not load library. Reasons: [no leveldbjni64-1.8 in java.library.path, no leveldbjni-1.8 in java.library.path, no leveldbjni in java.library.path]
    at org.fusesource.hawtjni.runtime.Library.doLoad(Library.java:182)
    at org.fusesource.hawtjni.runtime.Library.load(Library.java:140)
    at org.fusesource.leveldbjni.JniDBFactory.<clinit>(JniDBFactory.java:48)
    at Test.main(Test.java:13)

Refer to Fusessource's Leveldb's readme to solve this problem

Only need to import the Leveldbjni-win64-1.8.jar into the project (should be run under Win64)

To set up a project maven dependency:

<dependency>
    <groupId>org.fusesource.leveldbjni</groupId>
    <artifactId>leveldbjni-win64</artifactId>
    <version>99-master-SNAPSHOT</version>
</dependency>

<dependency>
      <groupId>org.fusesource.leveldbjni</groupId>
      <artifactId>leveldbjni</artifactId>
      <version>99-master-SNAPSHOT</version>
</dependency>

I used the Gradle management project to add in the project Build.gradle dependencies

 
compile "org.fusesource.leveldbjni:leveldbjni:1.8"
compile "org.fusesource.leveldbjni:leveldbjni-win64:1.8"

Two lines, then update the item to

Reference: Https://github.com/fusesource/leveldbjni

PS. What is Java.library.path

Java typically uses two Path:classpath and Java.library.path

Classpath is the location that points to the jar package

Java.library.path the location of the non-Java class package (DLL,SO), Java.library.path can be viewed through System.getpropertu ("Java.library.path").

 
public static void main(String[] args){
  System.out.println("java.library.path: ");              
  System.out.println(System.getProperty("java.library.path"));
}

The output is:

 
java.library.path: 
D:\Java\jdk1.8.0_91\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;D:/Jav。。。。

	 

No leveldbjni64-1.8 in Java.library.path