我有以下程序可以在一个简单的文件上运行，但是在Car.class上运行时会挂在p.waitFor（）上
更新：当我删除p.waitFor（）行时；该程序在更复杂的Car.class文件上运行。那么，为什么将其挂起，我需要将其保留在代码中？
这是程序：
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class Javap2 {
public static void main(String[] args) {
try{
List<String> cmdList = new ArrayList<String>();
cmdList.add("javap.exe");
cmdList.add("-c");
cmdList.add("E:\\JAVA\\BlueJ\\PROJECTS\\cars\\DocFooter.class");
System.out.println(0);
// Constructing ProcessBuilder with List as argument
ProcessBuilder pb = new ProcessBuilder(cmdList);
System.out.println(1);
Process p = pb.start();
System.out.println(2);
p.waitFor();
System.out.println(3);
InputStream fis = p.getInputStream();
System.out.println(4);
DisplayClassStructure(fis);
}catch(Exception e){
System.out.println(e);
}
}
// Method used for displaying the disassembled class
private static void DisplayClassStructure(InputStream is) throws IOException{
InputStream stream;
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String line;
List<String> commands = new ArrayList<String>();
String[] ifs = {": if_",": ifeq",": ifge",": ifgt",": ifle",": iflt",": ifne",": ifnonnull",": ifnull"};
int i =0;
while ((line = reader.readLine()) != null) {
commands.add(line.trim());
i++;
}
// Better put it in finally
reader.close();
for (int j = 0; j < i; j++){
System.out.println(j + " " + commands.get(j));
}
}
}
这是适用于DocFooter.java的简单案例：
public class DocFooter {
public void init()
{
int x = 5;
if(5 == x){
System.out.println("yes we are");
}
}
}
这是Car.java，当被Javap.class的主程序调用时，它不起作用：
import java.util.Random;
public class Car
{
/* This section declares our instance variables for the class */
private String make;
private int year;
private double mileage;
private int lastTireChange;
private String carColor;
/**
* Constructor for objects of class Car
*/
public Car()
{
// initialise instance variables
make = "defaultCar";
year = 1904;
mileage = 0.0;
carColor = "black";
lastTireChange = (int) mileage;
}
public Car(String updateMake, int updateYear, double updateMileage, String updateCarColor)
{
// initialise instance variables
make = updateMake;
year = updateYear;
mileage = updateMileage;
carColor = updateCarColor;
lastTireChange = (int) mileage;
}
public static void main(String[] args)
{
System.out.print('\u000C');
Car mine = new Car("BMzW",2018,60000.0,"blue"); //declareing a new Car
Car yours = new Car(); //declareing a new Car
System.out.println("Print out initial instance variables from both constructors");
System.out.println("BMzW,2018,60000.0,blue,60000");
System.out.println("default car,1904,0.0,black,0");
mine.printVars(mine);
yours.printVars(yours);
System.out.println("Print out values after each method has been called");
mine.callMethods(mine);
mine.oldCarNewColor();
}
public String getMake()
{
return make;
}
public void setMake(String updateMake)
{
make = updateMake;
}
public int getYear()
{
return year;
}
public void setYear(int updateYear)
{
year = updateYear;
}
public double getMileage()
{
return mileage;
}
public void setMileage(double updateMileage)
{
mileage = updateMileage;
}
public String getCarColor()
{
return carColor;
}
public void setCarColor(String updateCarColor)
{
carColor = updateCarColor;
}
public int getLastTireChange()
{
return lastTireChange;
}
public void setLastTireChange(int updateLastTireChange)
{
lastTireChange = updateLastTireChange;
}
public boolean tireChange()
{
if (mileage - (double)lastTireChange > 40000.){
setLastTireChange((int) getMileage());
return true;
}else return false;
}
public void oldCarNewColor() {
String[] colors = {"blue",
"black",
"brown",
"red",
"green",
"grey",
"white",
"yellow",
};
int size = colors.length; // local var array length
Random random = new Random(); // imported Random class now declaring a new instance
int index = random.nextInt(size); //local var index for use in String array
if (mileage > 50000) carColor = colors[index];
}
public void printVars(Car sample)
{
System.out.println("");
System.out.println("MAKE : " + sample.getMake());
System.out.println("YEAR : " + sample.getYear());
System.out.println("MILEAGE : " + sample.getMileage());
System.out.println("CAR COLOR : " + sample.getCarColor());
System.out.println("TIRE MILES : " + sample.getLastTireChange());
System.out.println("");
}
public void callMethods(Car sample){
System.out.println("");
sample.setMake("mercedes");
System.out.println("MAKE updated to (mercedes) : " + sample.getMake() );
sample.setYear(2000);
System.out.println("YEAR updated to (2000) : " + sample.getYear());
sample.setMileage(75000.0);
System.out.println("MILEAGE updated to (75000.0) : " + sample.getMileage());
sample.setCarColor("red");
System.out.println("CAR COLOR updated to (red) : " + sample.getCarColor());
sample.setLastTireChange(15000);
System.out.println("TIRE MILES updated to (15000) : " + sample.getLastTireChange());
System.out.println();
System.out.println("Call method tireChange - expect true");
System.out.println(sample.tireChange());
System.out.println("TIRE MILES updated to (75000) : " + sample.getLastTireChange());
System.out.println();
System.out.println("Call method tireChange again - expect false");
System.out.println(sample.tireChange());
System.out.println("TIRE MILES updated to (no change): " + sample.getLastTireChange());
System.out.println();
sample.oldCarNewColor();
System.out.println("CAR COLOR updated to (random color): " + sample.getCarColor());
}
}