問題描述

基本類型的包裝類的parseparseXXX(String)和valueOf(String)有什么區別呀？

問題解答

JDK8源碼

/** * Returns an {@code Integer} object holding the value * extracted from the specified {@code String} when parsed * with the radix given by the second argument. The first argument * is interpreted as representing a signed integer in the radix * specified by the second argument, exactly as if the arguments * were given to the {@link #parseInt(java.lang.String, int)} * method. The result is an {@code Integer} object that * represents the integer value specified by the string. * * <p>In other words, this method returns an {@code Integer} * object equal to the value of: * * <blockquote> * {@code new Integer(Integer.parseInt(s, radix))} * </blockquote> * * @param s the string to be parsed. * @param radix the radix to be used in interpreting {@code s} * @return an {@code Integer} object holding the value * represented by the string argument in the specified * radix. * @exception NumberFormatException if the {@code String} * does not contain a parsable {@code int}. */public static Integer valueOf(String s, int radix) throws NumberFormatException { return Integer.valueOf(parseInt(s,radix));}

這里用Inteager來說明， valueOf 實際上調用了 parseInt。 parseInt方法是類Integer的靜態方法，它的作用就是將字符串轉化為整數int valueOf也是Integer類的靜態方法，它的作用是將字符串轉化為Integer對象