Java如何使用web3j调用智能合约

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

                            org.web3j            core            5.0.0                            org.web3j            codegen            5.0.0                                    org.fisco-bcos            solcJ            0.5.2.0                                    commons-io            commons-io            2.4                                    com.squareup.okhttp3            okhttp            4.4.0                                    com.squareup.okhttp3            okhttp-ws            3.4.2        

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是什么

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。

感谢你的阅读，相信你对"Java如何使用web3j调用智能合约"这一问题有一定的了解，快去动手实践吧，如果想了解更多相关知识点，可以关注网站！小编会继续为大家带来更好的文章！