Runtime.getRuntime.exec(String)与exec(String[])的区别

Runtime.getRuntime.exec(String)

这个方法传入的是字符串，JAVA内部处理时会对字符串进行分割成数据，然后调用exec(String[],null,null)方法

public Process exec(String command) throws IOException {
return exec(command, null, null);
}
public Process exec(String command, String[] envp, File dir)
throws IOException {
if (command.length() == 0)
throw new IllegalArgumentException("Empty command");
StringTokenizer st = new StringTokenizer(command);
String[] cmdarray = new String[st.countTokens()];
for (int i = 0; st.hasMoreTokens(); i++)
cmdarray[i] = st.nextToken();
return exec(cmdarray, envp, dir);
public Process exec(String[] cmdarray, String[] envp, File dir)
throws IOException {
return new ProcessBuilder(cmdarray)
.environment(envp)
.directory(dir)
.start();
}

Runtime.getRuntime.exec(String[])

该方法会最后也是执行exec(String[],null,null)

public Process exec(String cmdarray[]) throws IOException {
return exec(cmdarray, null, null);
}
public Process exec(String[] cmdarray, String[] envp, File dir)
throws IOException {
return new ProcessBuilder(cmdarray)
.environment(envp)
.directory(dir)
.start();
}

从上面可以看出，如果执行一整条已经拼接好的命令时，可以用exec(String);如果命令参数分开时，可以用exec(String[]);如果把一条已经拼接好的字符串执行第二个方法，就会报命令找不到。