解决JAVA中Runtime.getRuntime().exec()方法启动子进程时候出现阻塞问题

川长思鸟来 2022-12-25 06:57 118阅读 0赞

### 文章目录 ###

*  问题描述
 *  有问题的代码
 *  能正常运行的代码
 *   *  新建一个线程接受子进程控制台输出信息
     *  main函数代码

# 问题描述 #

本人在开发中遇到通过Process类启动子进程的时候出现子进程一直阻塞,排查了子进程程序代码没有问题代码，然后偶然找到一个大佬写的博客才解决了此问题,**需要单独启动一个新的线程接受子进程控制台的输出信息方可解决。**

# 有问题的代码 #

public static void main(String[] args) throws Exception { 
            String osname = System.getProperty("os.name").toLowerCase();
            StringBuilder command = new StringBuilder("java -Xms512M -Xmx512M -jar test.jar --server.port=8080 ");
            Process process=null;
            try { 
                if ( osname != null && osname.indexOf("linux") != -1) { 
                    String[] cmdA = { "/bin/sh", "-c", command.toString()};
                    ProcessBuilder pb = new ProcessBuilder(cmdA);
                    process = pb.start();;
                } else { 
                    process =  Runtime.getRuntime().exec(command.toString());
                }
                InputStreamReader isr = new InputStreamReader(process.getInputStream());
                BufferedReader br = new BufferedReader(isr);
                String line;
                while ((line = br.readLine()) != null) { 
                    System.out.println("INFO" + ">" + line);
                }
                process.waitFor();
            }catch (InterruptedException e){ 
                process.destroyForcibly();
            }
        }

# 能正常运行的代码 #

## 新建一个线程接受子进程控制台输出信息 ##

public class StreamGobble extends Thread  { 
        InputStream is;
        String type;
    
        public StreamGobble(InputStream is, String type) { 
            this.is = is;
            this.type = type;
        }
        @Override
        public void run() { 
            try { 
                InputStreamReader isr = new InputStreamReader(is);
                BufferedReader br = new BufferedReader(isr);
                String line = null;
                while ((line = br.readLine()) != null) { 
                    System.out.println(type + ">" + line);
                }
            } catch (IOException ioe) { 
                ioe.printStackTrace();
            }
        }
    
    }

## main函数代码 ##

public static void main(String[] args) throws Exception { 
            String osname = System.getProperty("os.name").toLowerCase();
            StringBuilder command = new StringBuilder("java -Xms512M -Xmx512M -jar test.jar --server.port=8080 ");
            Process process=null;
            try { 
                if ( osname != null && osname.indexOf("linux") != -1) { 
                    String[] cmdA = { "/bin/sh", "-c", command.toString()};
                    ProcessBuilder pb = new ProcessBuilder(cmdA);
                    process = pb.start();;
                } else { 
                    process =  Runtime.getRuntime().exec(command.toString());
                }
                new StreamGobble(process.getInputStream(), "INFO").start();
                new StreamGobble(process.getErrorStream(), "ERROR").start();
                process.waitFor();
            }catch (InterruptedException e){ 
                process.destroyForcibly();
            }
        }