专业网站制作需要多少钱,什么叫手机网站,网站打开时的客户引导页,360营销平台一般我们使用Java运行其他类中的方法的时候#xff0c;无论是静态调用还是动态调用#xff0c;都是在当前的进程中执行的。也就是只有一个Java虚拟机实例在运行。有时候需要通过Java代码启动多个Java子进程#xff0c;这样做会消耗些资源#xff0c;但是程序变得更稳定。因…一般我们使用Java运行其他类中的方法的时候无论是静态调用还是动态调用都是在当前的进程中执行的。也就是只有一个Java虚拟机实例在运行。有时候需要通过Java代码启动多个Java子进程这样做会消耗些资源但是程序变得更稳定。因为新启动的进程是在不同的虚拟机中运行的。 在Windows中一个虚拟机就是一个 有两种方式调用一个进程 1、System.exec 子进程 1 package org.zln.thread;2 3 import java.io.File;4 import java.io.IOException;5 6 /**7 * Created by coolkid on 2015/6/21 0021.8 */9 public class TestFile {
10 public static void main(String[] args) {
11 try {
12 File file new File(D:\\my.txt);
13 file.createNewFile();
14 System.out.println(被调用成功!);
15
16 } catch (IOException e) {
17 e.printStackTrace();
18 }
19 }
20 } E:\GitHub\tools\JavaEEDevelop\Lesson1_JavaSe_Demo1\src\org\zln\thread\TestFile.java 主进程 1 package org.zln.thread;2 3 import java.io.IOException;4 5 /**6 * Created by coolkid on 2015/6/21 0021.7 */8 public class TestRuntime {9 public static void main(String[] args) {
10 String rootPath E:\\GitHub\\tools\\JavaEEDevelop\\out\\production\\Lesson1_JavaSe_Demo1;
11 String mainPath org.zln.thread.TestFile;
12 String command java -classpath rootPath mainPath;
13 Runtime runtime Runtime.getRuntime();
14 try {
15 System.out.println(command);
16 runtime.exec(command);
17
18 } catch (IOException e) {
19 e.printStackTrace();
20 }
21 }
22 } E:\GitHub\tools\JavaEEDevelop\Lesson1_JavaSe_Demo1\src\org\zln\thread\TestRuntime.java 调用发现在指定目录下创建了文件但是并没有在控制台输出信息。因为TestFile子进程并没有自己的控制台改进代码 1 package org.zln.thread;2 3 import java.io.*;4 5 /**6 * Created by coolkid on 2015/6/21 0021.7 */8 public class TestRuntime {9 public static void main(String[] args) {
10 String rootPath E:\\GitHub\\tools\\JavaEEDevelop\\out\\production\\Lesson1_JavaSe_Demo1;
11 String mainPath org.zln.thread.TestFile;
12 String command java -classpath rootPath mainPath;
13 Runtime runtime Runtime.getRuntime();
14 try {
15 System.out.println(command);
16 Process process runtime.exec(command);
17 BufferedReader bufferedReader new BufferedReader(new InputStreamReader(new BufferedInputStream(process.getInputStream())));
18 String line;
19 while ((line bufferedReader.readLine())!null){
20 System.out.println(子进程输出line);
21 }
22 bufferedReader.close();
23 } catch (IOException e) {
24 e.printStackTrace();
25 }
26 }
27 } E:\GitHub\tools\JavaEEDevelop\Lesson1_JavaSe_Demo1\src\org\zln\thread\TestRuntime.java 这里不知为何在IDE中运行输出的是乱码在控制台运行则不是乱码 既然父进程可以获取到子进程的输出那么父进程如何发送消息给子进程呢 子进程修改 1 package org.zln.thread;2 3 import java.io.BufferedReader;4 import java.io.File;5 import java.io.IOException;6 import java.io.InputStreamReader;7 8 /**9 * Created by coolkid on 2015/6/21 0021.
10 */
11 public class TestFile {
12 public static void main(String[] args) {
13 try {
14 File file new File(D:\\my.txt);
15 file.createNewFile();
16 System.out.println(被调用成功!);
17
18 BufferedReader bufferedReader new BufferedReader(new InputStreamReader(System.in));
19 System.out.println(父进程输入信息bufferedReader.readLine());
20
21 } catch (IOException e) {
22 e.printStackTrace();
23 }
24 }
25 } E:\GitHub\tools\JavaEEDevelop\Lesson1_JavaSe_Demo1\src\org\zln\thread\TestFile.java 父进程修改 1 package org.zln.thread;2 3 import java.io.*;4 5 /**6 * Created by coolkid on 2015/6/21 0021.7 */8 public class TestRuntime {9 public static void main(String[] args) {
10 String rootPath E:\\GitHub\\tools\\JavaEEDevelop\\out\\production\\Lesson1_JavaSe_Demo1;
11 String mainPath org.zln.thread.TestFile;
12 String command java -classpath rootPath mainPath;
13 Runtime runtime Runtime.getRuntime();
14 try {
15 System.out.println(command);
16 Process process runtime.exec(command);
17 /*向子进程输入*/
18 BufferedWriter bufferedWriter new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
19 bufferedWriter.write(Hello 子进程!);
20 bufferedWriter.close();/*必须现在就关闭否则无法向子进程输入信息*/
21 /*获取子进程输出*/
22 BufferedReader bufferedReader new BufferedReader(new InputStreamReader(new BufferedInputStream(process.getInputStream())));
23 String line;
24 while ((line bufferedReader.readLine())!null){
25 System.out.println(子进程输出line);
26 }
27 bufferedReader.close();
28 } catch (IOException e) {
29 e.printStackTrace();
30 }
31 }
32 } E:\GitHub\tools\JavaEEDevelop\Lesson1_JavaSe_Demo1\src\org\zln\thread\TestRuntime.java 2、使用ProcessBuilder建立子进程 1 package org.zln.thread;2 3 import java.io.*;4 5 /**6 * Created by coolkid on 2015/6/21 0021.7 */8 public class TestProcessBuilder {9 public static void main(String[] args) throws IOException {
10 ProcessBuilder processBuilder new ProcessBuilder(java,org.zln.thread.TestFile);
11 /*设置工作目录*/
12 processBuilder.directory(new File(E:\\GitHub\\tools\\JavaEEDevelop\\out\\production\\Lesson1_JavaSe_Demo1));
13 Process process processBuilder.start();
14
15 /*向子进程输入*/
16 BufferedWriter bufferedWriter new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
17 bufferedWriter.write(Hello 子进程!);
18 bufferedWriter.close();/*必须现在就关闭否则无法向子进程输入信息*/
19 /*获取子进程输出*/
20 BufferedReader bufferedReader new BufferedReader(new InputStreamReader(new BufferedInputStream(process.getInputStream())));
21 String line;
22 while ((line bufferedReader.readLine())!null){
23 System.out.println(子进程输出line);
24 }
25 bufferedReader.close();
26
27
28 }
29 } E:\GitHub\tools\JavaEEDevelop\Lesson1_JavaSe_Demo1\src\org\zln\thread\TestProcessBuilder.java 转载于:https://www.cnblogs.com/sherrykid/p/4592195.html
