Question

当我运行我的程序时，我得到了这个：

run:
Planetary DataPlanet   Diameter(km)   Mass(kg)   g(m/s^2)
_________________________________________________
Exception in thread "main" java.util.IllegalFormatPrecisionException: 1
Mercury at java.util.Formatter$FormatSpecifier.checkInteger(Formatter.java:2936)
at java.util.Formatter$FormatSpecifier.<init>(Formatter.java:2684)
at java.util.Formatter.parse(Formatter.java:2528)
at java.util.Formatter.format(Formatter.java:2469)
at java.io.PrintStream.format(PrintStream.java:970)
at java.io.PrintStream.printf(PrintStream.java:871)
at GravityV1.diameterr(GravityV1.java:45)
at GravityV1.main(GravityV1.java:73)
Java Result: 1
BUILD SUCCESSFUL (total time: 6 seconds)

我正在尝试在main方法中显示由静态方法生成的信息。不知何故，当我在main方法中调用它时它没有显示它，我也在尝试计算引力并且它没有识别我的一些变量，比如引力的通用常数，我使重力静态方法高于主要方法并在主要计算方法中声明和初始化万有引力常数。任何帮助将不胜感激。以下是我的代码：

public class GravityV1 {

// title static method
public static void title(){

    // title
    System.out.printf("%10s", "Planetary Data");

    // heading
    System.out.println("Planet   Diameter(km)   Mass(kg)   g(m/s^2)");

    // create line
    System.out.println("_________________________________________________");
}

// months static method
public static void planetss(){

    // create months array
    String[] planets = {"Mercury", "Venus", "Earth", "Mars", "Jupiter", 
        "Saturn", "Uranus", "Neptune"};

    // display planets
    System.out.printf("%5s", (Object[]) planets);
}

// diameter static method
public static void diameterr(){

    // create array of diameter
    double[] diameter = {4880, 12103.6, 12756, 6794, 142984, 120536, 51118, 
        49532};

    // display diameter
    System.out.printf("%4.1d", diameter);
}

// mass static method
public static void masss(){

    // create array of mass
    double[] mass = {3.30E23, 4.869E24, 5.97E24, 6.4219E23, 1.900E27, 
        5.68E26, 8.683E25, 1.0247E26};

    // display mass
    System.out.printf("%4.1d", mass);
}

// gravity calculation static method
public static double gravity(double g){

    // calculate gravity
    g = (G * mass) / Math.pow(diameter / 2, 2);

    return g;
}

// main method
public static void main(String args[]){

    title();
    planetss();
    diameterr();
    masss();

    double G = 6.67384 * Math.pow(10, -11);
}
}

Answer 1

double类型的

Format specifier不是d，而是f。您应该将printf方法中的diameterr语句替换为：

System.out.printf("%4.1f", diameter);

java在静态方法和main方法中使用变量声明和初始化

1 个答案: