【Android】java中调用JS的方法

最近因为学校换了新的教务系统，想做一个模拟登陆功能，发现登陆的账号和密码有一个js脚本来进行加密

整理了一下java中执行JS的方法

智强教务 账号 密码 加密方法

var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

function encodeInp(input) {
    var output = "";
    var chr1, chr2, chr3 = "";
    var enc1, enc2, enc3, enc4 = "";
    var i = 0;
    do {
        chr1 = input.charCodeAt(i++);
        chr2 = input.charCodeAt(i++);
        chr3 = input.charCodeAt(i++);
        enc1 = chr1 >> 2;
        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
        enc4 = chr3 & 63;
        if (isNaN(chr2)) {
            enc3 = enc4 = 64
        } else if (isNaN(chr3)) {
            enc4 = 64
        }
        output = output + keyStr.charAt(enc1) + keyStr.charAt(enc2) + keyStr.charAt(enc3) + keyStr.charAt(enc4);
        chr1 = chr2 = chr3 = "";
        enc1 = enc2 = enc3 = enc4 = ""
    } while (i < input.length);
    return output
}

Java

首先需要创建一个接口，接口中的抽象方法要和js中函数名保持一致

public interface Methods {
    public String encodeInp(String input);
}

然后在主函数中使用ScriptEngineManager来加载js

ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("javascript");
        FileReader fileReader=new FileReader("F:\JAVAProject\src\conwork.js");//js路径
        engine.eval(fileReader);
        if (engine instanceof Invocable) {
            Invocable invocable = (Invocable) engine;
            Methods executeMethod = invocable.getInterface(Methods.class);
            System.out.println(executeMethod.encodeInp("account"));
            System.out.println(executeMethod.encodeInp("password"));
        }

Android

由于安卓中没有ScriptEngineManager ，引入jar包后也无法使用（囧）

故使用J2V8这个第三方库来进行加载

implementation 'com.eclipsesource.j2v8:j2v8:4.5.0@aar'

将js文件放在assets文件夹下

然后在Activity中调用

public String encodeNumber()
    {
        String result="没有";
        InputStream is= null;   //获取用户名与密码加密的js代码
        try {
            is = getAssets().open("conwork.js");
        } catch (IOException e) {
            e.printStackTrace();
        }
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();
        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
            V8 runtime = V8.createV8Runtime();      //使用J2V8运行js代码并将编码结果返回
            final String encodename = runtime.executeStringScript(sb.toString()
                    + "encodeInp('account');
");
            final String encodepwd=runtime.executeStringScript(sb.toString()+"encodeInp(password');
");
            runtime.release();
            result=encodename+"%%%"+encodepwd;
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
       return result;
    }