我找到了几个通过Java类运行cmd命令的代码片段，但我无法理解它。
以下是用于打开cmd的代码
public void excCommand(String new_dir){
Runtime rt = Runtime.getRuntime();
try {
rt.exec(new String[]{"cmd.exe","/c","start"});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
我还找到了其他链接，可以添加其他命令，例如cd命令 http://www.coderanch.com/t/109753/Linux-UNIX/exec-command-cd-command-java
有人可以帮助我理解如何cd到一个目录吗，例如：
cd C:\Program Files\Flowella
然后在该目录上运行其他命令？
public class Demo {
public static void main(String args[]) throws IOException {
Process process = Runtime.getRuntime().exec("/Users/******/Library/Android/sdk/platform-tools/adb" + " shell dumpsys battery ");
BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
while (true) {
line = in.readLine();
if (line == null) { break; }
System.out.println(line);
}
}
}
在Java中执行CMD的一种方式！
public void executeCmd() {
String anyCommand="your command";
try {
Process process = Runtime.getRuntime().exec("cmd /c start cmd.exe /K " + anyCommand);
} catch (IOException e) {
e.printStackTrace();
}
}
这里的价值在于使用&符号批处理命令以及正确的格式来使用cd更改驱动器。
public class CmdCommander {
public static void main(String[] args) throws Exception {
//easyway to start native windows command prompt from Intellij
/*
Rules are:
1.baseStart must be dual start
2.first command must not have &.
3.subsequent commands must be prepended with &
4.drive change needs extra &
5.use quotes at start and end of command batch
*/
String startQuote = "\"";
String endQuote = "\"";
//String baseStart_not_taking_commands = " cmd /K start ";
String baseStart = " cmd /K start cmd /K ";//dual start is must
String first_command_chcp = " chcp 1251 ";
String dirList = " &dir ";//& in front of commands after first command means enter
//change drive....to yours
String changeDir = " &cd &I: ";//extra & makes changing drive happen
String javaLaunch = " &java ";//just another command
String javaClass = " Encodes ";//parameter for java needs no &
String javaCommand = javaLaunch + javaClass;
//build batch command
String totalCommand =
baseStart +
startQuote +
first_command_chcp +
//javaCommand +
changeDir +
dirList +
endQuote;
System.out.println(totalCommand);//prints into Intellij terminal
runCmd(totalCommand);
//Thread t = Thread.currentThread();
//t.sleep(3000);
System.out.println("loppu hep");//prints into Intellij terminal
}
public static void runCmd(String command) throws Exception {
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(command);
}
}
(就像其他人说的那样) 对于简单的命令，你可以直接执行，例如：
Runtime.getRuntime().exec("cmd /c mkdir H:\\test\\BBB");
(cmd /c 可能是必需的)
然而，对于一些复杂的命令，你可能需要执行一个双重的 cmd.exe /c cmd.exe /c，
否则（如果你只使用一个），cmd会被静默地丢弃，
（或者如果你不使用/c或使用一些奇怪的/c cmd组合模式，cmd可能会冻结），
我不知道为什么。
((我是如何发现它的？-- 我无法让它工作并尝试了多次；有一次我意外地复制了cmd并运行了它，然后发现了这个问题。))
@eg::
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class T1 {
static String convertStreamToString(java.io.InputStream is) {
java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
return s.hasNext() ? s.next() : "";
}
public static void main(String[] args) throws InterruptedException, IOException {
Process process;
System.out.println("---"); // creates a folder `BBB`
Runtime.getRuntime().exec("cmd /c mkdir H:\\test\\BBB");
// System.out.println("---");
// idk how to do `cd`
System.out.println("---"); // list file & folder in C:\
process = Runtime.getRuntime().exec("cmd.exe /c dir C:\\");
System.out.println(convertStreamToString(process.getInputStream()));
System.out.println("---"); // echo
process = Runtime.getRuntime().exec("cmd.exe /c echo \"Some Line\"");
System.out.println(convertStreamToString(process.getInputStream()));
// @atten: notice the double `cmd.exe /c cmd.exe /c `
// -- idk why must double - otherwise this wont execute
System.out.println("---"); // uses mysqldump to do something
process = Runtime.getRuntime().exec("cmd.exe /c cmd.exe /c \"C:\\Program Files\\MySQL\\MySQL Server 8.0\\bin\\mysqldump.exe\" -u root -pmysql db_drawandchat_01 > \"H:\\DrawAndChatApp_db\\DrawAndChat_20230503_0134_03326.sql\"");
}
// Output::
//
// ---
// ---
// Volume in drive C has no label.
// Volume Serial Number is 2C83-063F
//
// Directory of C:\
//
// 2019/06/29 11:56 <DIR> Intel
// 2022/04/18 06:07 <DIR> log
// 2019/12/07 17:14 <DIR> PerfLogs
// 2023/04/22 01:13 <DIR> Program Files
// 2023/04/08 21:27 <DIR> Program Files (x86)
// 2020/12/08 00:15 <DIR> Untitled
// 2021/04/23 04:57 <DIR> Users
// 2023/04/25 09:33 <DIR> Windows
// 0 File(s) 0 bytes
// 8 Dir(s) 3,268,296,704 bytes free
//
// ---
// "Some Line"
//
// ---
}
更新
根据我的经验
ProcessBuilder 使用 字符串数组作为参数 是更好的选择。
@注意：
使用字符串数组作为参数，不要使用整个字符串，否则解析可能会出错。
CreateProcess error=2，系统找不到指定的文件
删除不必要的双引号（例如：在执行路径周围的引号）
（因为您正在使用数组，所以空格路径cmd问题已经被消除了//实际上并没有，见下面的更新->仍然使用[a double cmd.exe /c cmd.exe /c]）。
Java-ProcessBuilder命令参数带有空格和双引号失败
该数组基于“exec&flag&arg&path”分隔
--通常，在任何空格处分隔（尽管不在路径上）
-pPASSWORD@eg:: [将字符串命令转换为ProcessBuilder中的数组命令]
（以下代码在一些小修改后曾经工作过，但是没有测试）
public class T1 {
public static void main(String[] args) throws InterruptedException, IOException {
String cmdStr_loadFile = "cmd.exe /c cmd.exe /c "
+ "\"C:\\Program Files\\MySQL\\MySQL Server 8.0\\bin\\mysql.exe\" "
+ "-u root "
+ "-pmysql "
+ "--database db_drawandchat_02 "
+ "< "
+ "\"H:\\DrawAndChatApp_db\\DrawAndChat_test.sql\"";
ArrayList<String> cmdArr_loadFile = new ArrayList<>(Arrays.asList("cmd", "/c",
"C:\\Program Files\\MySQL\\MySQL Server 8.0\\bin\\mysql.exe",
"-u", "root",
"-pmysql",
"--database", "db_drawandchat_02",
"<",
"H:\\DrawAndChatApp_db\\DrawAndChat_test.sql"));
try {
// Process process = Runtime.getRuntime().exec(cmdStr_loadFile);
ProcessBuilder processBuilder = new ProcessBuilder(cmdArr_loadFile);
// processBuilder.directory(new File("H:/"));
processBuilder.redirectOutput(Redirect.INHERIT);
processBuilder.redirectError(Redirect.INHERIT);
// processBuilder.redirectInput(Redirect.INHERIT);
Process process = processBuilder.start();
try {
process.waitFor(20, TimeUnit.SECONDS);
// System.out.println(StringUtil.convertStreamToString(process.getInputStream()));
} catch (InterruptedException e) {
throw new Error(e);
}
} catch (IOException e) {
throw new Error(e);
}
}
}
更新
在使用 >"a double cmd.exe /c cmd.exe /c"
的情况下，使用 >"ProcessBuilder with array of String as args" 也是可行的。
特别是当你的路径中存在空格-- 可执行文件路径&&文件路径参数都包含空格时
@例如::
ArrayList<String> cmdArr_saveFile = new ArrayList<>(
Arrays.asList("cmd", "/c", "cmd", "/c",
"C:\\Program Files\\MySQL\\MySQL Server 8.0\\bin\\mysqldump.exe",
"-u", "root",
"-pmysql",
"db_drawandchat_01",
">",
"H:\\DrawAndChatApp_db\\DrawAndChat test2.sql"));
然而，如果您的参数中有空格（不是文件路径参数），
它仍然无法工作...
相关链接：java ProcessBuilder in Windows spaces in *.exe path and in argument
[[我确实想知道为什么“双倍cmd.exe /c cmd.exe /c”可以工作/ Java进程cmd解析如何工作。]]