What is the difference between MessageFormat.format and String.format in JDK 1.5?
What is the difference between MessageFormat.format
and String.format
in JDK 1.开发者_如何学编程5?
Put simply, the main difference is in format string:
MessageFormat.format()
format string accepts argument positions (eg.{0}
,{1}
). Example:"This is year {0}!"
The developer doesn't have to worry about argument types, because they are, most often, recognized and formated according to current
Locale
.String.format()
format string accepts argument type specifiers (eg.%d
for numbers,%s
for strings). Example:"This is year %d!"
String.format()
generally gives you much more control over how the argument is displayed thanks to many options you can specify with the type specifier. For instance, format string"%-6.2f"
specifies to display a left-aligned floating point number with min. width 6 chars and precision of 2 decimal places.
Just have a look at javadoc of both methods to find out more details.
String.format is just a shortcut to Formatter, this is a "printf-style" formatter. On the other side, MessageFormat uses a different formatting convention, as described in the linked documentation.
Use the first "for layout justification and alignment, common formats for numeric, string, and date/time data, and locale-specific output" and the second "to produce concatenated messages in language-neutral way".
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