我正在嘗試使用ProcessBuilder將python腳本的返回值獲取到Java中。我期望在Java中具有“這就是我正在尋找的”的值。誰能告訴我下面的邏輯中有什么問題？我正在使用python3，并希望使用java標(biāo)準(zhǔn)庫來完成此操作。test.py 代碼import sysdef main33(): return "This is what I am looking for"if __name__ == '__main__': globals()[sys.argv[1]]()Java 代碼String filePath = "D:\\test\\test.py";ProcessBuilder pb = new ProcessBuilder().inheritIO().command("python", "-u", filePath, "main33");Process p = pb.start();int exitCode = p.waitFor();BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));String line = "";line = in.readLine();while ((line = in.readLine()) != null){ line = line + line;}System.out.println("Process exit value:"+exitCode);System.out.println("value is : "+line);in.close();輸出Process exit value:0value is : null
2 回答
守候你守候我
TA貢獻(xiàn)1802條經(jīng)驗 獲得超10個贊
當(dāng)您從另一個進(jìn)程生成一個進(jìn)程時，它們只能（主要是）通過其輸入和輸出流進(jìn)行通信。因此，你不能期望 python 中 main33（） 的返回值到達(dá) Java，它將僅在 Python 運(yùn)行時環(huán)境中結(jié)束其生命周期。如果你需要把一些東西發(fā)回Java進(jìn)程，你需要把它寫到print（）。
修改了 python 和 java 代碼片段。
import sys
def main33():
print("This is what I am looking for")
if __name__ == '__main__':
globals()[sys.argv[1]]()
#should be 0 for successful exit
#however just to demostrate that this value will reach Java in exit code
sys.exit(220)
public static void main(String[] args) throws Exception {
String filePath = "D:\\test\\test.py";
ProcessBuilder pb = new ProcessBuilder()
.command("python", "-u", filePath, "main33");
Process p = pb.start();
BufferedReader in = new BufferedReader(
new InputStreamReader(p.getInputStream()));
StringBuilder buffer = new StringBuilder();
String line = null;
while ((line = in.readLine()) != null){
buffer.append(line);
}
int exitCode = p.waitFor();
System.out.println("Value is: "+buffer.toString());
System.out.println("Process exit value:"+exitCode);
in.close();
}
守著一只汪
TA貢獻(xiàn)1872條經(jīng)驗 獲得超4個贊
您過度使用了變量 。它不能既是當(dāng)前的輸出線，也不能是到目前為止看到的所有線。添加第二個變量以跟蹤累積輸出。line
String line;
StringBuilder output = new StringBuilder();
while ((line = in.readLine()) != null) {
output.append(line);
.append('\n');
}
System.out.println("value is : " + output);
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