java.lang.NoSuchMethodError:: okhttp3.RequestBody.create(Ljava/lang/String;Lokhttp3/MediaType;)Lokht

解决办法: 在pom.xml中加入如下两个依赖

<dependency>
    <groupId>org.web3j</groupId>
    <artifactId>core</artifactId>
    <version>5.0.0</version>
</dependency>

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.3.1</version>
</dependency>