原来一直用C写的温控，但是想实现的很多功能都做不到——主要是C学得一点毛皮就开始写——但是习惯了Java想要什么功能就有什么包，以及成熟的IDE（好吧就是我智障总是写bug），所以决定改写成Java版本的。但是之前一直习惯了C和Linux的紧密相连，思路也是shell的思路，所以在Java里面也下意识想要用Process类的exec()来执行echo命令——风扇控制、频率限制都是通过写入文件来实现的。实际上因为exec()并不是一个shell，所以这样做是不行的。要想写入文件，还是要通过正式的FileWriter等类来实现。
现在剩下的问题是怎么在IDE里实现用root权限测试程序，不然每次都要去terminal里sudo真是很烦恼。
参考了： Java FileWriter类 Java FileReader类 CSDN - Java将字符串写入文件与将文件内容读取到字符串 Techie Delight - Convert char array to String in Java CSDN - intellij idea 导出可执行jar
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import java.io.*;
import static java.lang.Thread.sleep;
public class Thermal {
private static int[] tempSteps = {48, 50, 55, 60, 70, 80, 84, 90};
private static Boolean freqLimitOn = false;
private static int temperatureReader() throws IOException {
char[] temp = new char[2];
FileReader reader0 = new FileReader(new File("/sys/class/thermal/thermal_zone0/temp"));
FileReader reader1 = new FileReader(new File("/sys/class/thermal/thermal_zone1/temp"));
reader0.read(temp);
int temp0 = Integer.parseInt(String.valueOf(temp));
reader1.read(temp);
int temp1 = Integer.parseInt(String.valueOf(temp));
return ((temp0 >= temp1) ? temp0 : temp1);
}
private void fancontroller(int level) throws IOException {
FileWriter fw = new FileWriter("/proc/acpi/ibm/fan", false);
fw.write("level " + level);
fw.flush();
}
private void levelJudge(int temperature) throws IOException {
for (int i = tempSteps.length - 1; i >= 0; i--) {
if (temperature >= tempSteps[i]) {
fancontroller(i);
break;
}
}
}
private static void freqLimitSetter(long freq) throws IOException {
FileWriter fw;
String filepath;
for (int i = 0; i <= 7; i++) {
filepath = String.format("/sys/devices/system/cpu/cpufreq/policy%d/scaling_max_freq", i);
fw = new FileWriter(filepath, false);
fw.write("" + freq);
fw.flush();
fw.close();
}
}
private void freqthrottle() throws IOException {
if ((temperatureReader() > 84) && !freqLimitOn) {
freqLimitSetter(2100000);
freqLimitOn = true;
System.out.println("limited cpu freq");
} else if (freqLimitOn) {
freqLimitSetter(3500000);
System.out.println("unlimited cpu freq");
}
}
public static void main(String[] args) {
Thermal thermal = new Thermal();
try {
while (true) {
thermal.levelJudge(temperatureReader());
thermal.freqthrottle();
sleep(5000);
}
} catch (InterruptedException | IOException e) {
e.printStackTrace();
}
}
}