java - 定义的静态变量计数

Question

我对java有点新,我想知道是否可以检索已使用特定名称定义的静态变量的数量？例如:

public static final String DB_CTRLDATA              = "controldata";
public static final String DB_CTRLDATA_CELLADDR     = DB_CTRLDATA  + ".cell_addr";
public static final String DB_CTRLDATA_ID           = DB_CTRLDATA  + ".id";
public static final String DB_CTRLDATA_PRICT        = DB_CTRLDATA  + ".pri_count";
public static final String DB_CTRLDATA_RMODE        = DB_CTRLDATA  + ".rmode";
public static final String DB_CTRLDATA_TOD          = DB_CTRLDATA  + ".tod";
public static final String DB_DWELLDATA             = "dwelldata";
public static final String DB_DWELLDATA_FILENAME    = DB_DWELLDATA + ".filename";
public static final String DB_DWELLDATA_ID          = DB_DWELLDATA + ".id";
public static final String DB_DWELLDATA_OFFSET      = DB_DWELLDATA + ".offset";
public static final String DB_DWELLDATA_SIZE        = DB_DWELLDATA + ".size";
public static final String DB_POSTPROC              = "postproc";
public static final String DB_POSTPROC_ID           = DB_POSTPROC  + ".id";
public static final String DB_POSTPROC_PRESENT      = DB_POSTPROC  + ".present";

我想知道用名称DB_*定义了多少个对象.我知道将所有这些放在一个数组中是一个解决方案.

谢谢!

Answer 1

您可以使用反射来执行此操作.您可以使用该Class.getDeclaredFields()方法访问类中定义的所有字段.然后你可以迭代这些字段并使用Field.getModifiers()和检查它们的修饰符Modifier.isStatic(int).如果是字段static,则可以检查其名称uisng Field.getName().一个简短的例子:

int count = 0;
for (Field field : MyClassName.class.getDeclaredFields()) {
    int modifiers = field.getModifiers();
    if (Modifier.isStatic(modifiers)) {
        if (field.getName().startsWith("DB_")) {
            count++;
        }
    }
}

请注意,您必须处理SecurityException抛出的内容Class.getDeclaredFields().