这篇文章的内容主要围绕Java如何使用web3j调用智能合约进行讲述,文章内容清晰易懂,条理清晰,非常适合新手学习,值得大家去阅读。感兴趣的朋友可以跟随小编一起阅读吧。希望大家通过这篇文章有所收获!
1.Java程序引入相关依赖,后面用于调用智能合约中的函数
<!-- https://mvnrepository.com/artifact/org.web3j/core -->
<dependency>
<groupId>org.web3j</groupId>
<artifactId>core</artifactId>
<version>5.0.0</version>
</dependency>
<dependency>
<groupId>org.web3j</groupId>
<artifactId>codegen</artifactId>
<version>5.0.0</version>
</dependency>
<!-- 由于ether-camp/solcJ不再维护,所以使用了FISCO-BCOS/solcj -->
<dependency>
<groupId>org.fisco-bcos</groupId>
<artifactId>solcJ</artifactId>
<version>0.5.2.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp -->
<dependency>
<groupId>com.squareup.okhttp3</groupId>
<artifactId>okhttp</artifactId>
<version>4.4.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp-ws -->
<dependency>
<groupId>com.squareup.okhttp3</groupId>
<artifactId>okhttp-ws</artifactId>
<version>3.4.2</version>
</dependency>
2.将合约使用remix进行编译
编译后,复制abi、Bytecode,放入指定位置,生成abi和bin文件
@Test
void generateABIAndBIN() {
String abi = "abi复制放这里";
String bin = "bin复制过来放这里";
String abiFileName = "abi文件名.abi";
String binFileName = "bin文件名.bin";
File abiFile = new File("E:\\solidity\\xx\\xx\\"+ abiFileName);
File binFile = new File("E:\\solidity\\xx\\xx\\"+ binFileName);
if (!abiFile.getParentFile().exists()) {
boolean result = abiFile.getParentFile().mkdirs();
if (!result) {
System.out.println("创建失败");
}
}
BufferedOutputStream abiBos = null;
BufferedOutputStream binBos = null;
try {
FileOutputStream abiFos = new FileOutputStream(abiFile);
FileOutputStream binFos = new FileOutputStream(binFile);
abiBos = new BufferedOutputStream(abiFos);
binBos = new BufferedOutputStream(binFos);
abiBos.write(abi.getBytes());
abiBos.flush();
binBos.write(bin.getBytes());
binBos.flush();
}catch (Exception e) {
throw new RuntimeException("写入过程出现错误");
}finally {
if(abiBos != null) {
try {
abiBos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(binBos != null) {
try {
binBos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
3.使用codegen生成Java代码(参考https://github.com/maohuihua123/solidity-wrapper-generator)
使用该方法原因(ABI in solidity 0.6.0 does not have constant property which is causing UI libraries to think it's a non-constant method)
@Test
public void generateClass() throws IOException, ClassNotFoundException {
String[] args = Arrays.asList(
"-a", "D:/solidity/xx/xx.abi",
"-b", "D:/solidity/xx/xx.bin",
"-p", "top.rhynie.xx.contract",
"-o", "D:/IDEA_Project/xx/src/main/java"
).toArray(new String[0]);
Stream.of(args).forEach(System.out::println);
SolidityFunctionWrapperGenerator.main(args);
}
4.注册infura获取免费节点
5.java代码调用只能合约代码
@Test
void deployContract() throws Exception {
Web3j web3 = Web3j.build(new HttpService("https://ropsten.infura.io/v3/xxxx"));
String ownAddress = "0x119Eb8E686423E56b7cfc6F211C8CD4a9F71E3Cc";
// Credentials c = WalletUtils.loadCredentials("密码","keystore文件地址");
Credentials credentials = Credentials.create("私钥");
AWToken awToken = AWToken.deploy(web3, credentials, web3.ethGasPrice().send().getGasPrice(), Contract.GAS_LIMIT).send();
System.out.println(awToken.getContractAddress());
// 调用合约的函数
awToken.transfer("0x0", value);
}
Java是一门面向对象编程语言,可以编写桌面应用程序、Web应用程序、分布式系统和嵌入式系统应用程序。
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原文链接:https://my.oschina.net/Rhynie/blog/3209457