常用JDK及Java类库常量

fanlei77

已于 2023-08-16 18:19:17 修改

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分类专栏： JDK 文章标签： java

于 2022-08-19 22:34:46 首次发布

本文链接：https://blog.youkuaiyun.com/fanlei77/article/details/126432861

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本文介绍了JDK 8中的一些常见常量，如StandardCharsets、DayOfWeek等，并探讨了Apache Commons库如codec、Lang3中的关键常量，如CharEncoding、StringUtils等。同时，涵盖了Spring框架核心和Web模块中的系统属性、资源、MIME类型等常量，以及Guava库中的HttpHeaders常量。

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JDK 8

java.nio.charset.StandardCharsets

public static final Charset UTF_8 = Charset.forName("UTF-8");
public static final Charset UTF_16 = Charset.forName("UTF-16");
public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");

java.util.Locale

static public final Locale SIMPLIFIED_CHINESE = createConstant("zh", "CN");
static public final Locale TRADITIONAL_CHINESE = createConstant("zh", "TW");
static public final Locale FRANCE = createConstant("fr", "FR");
static public final Locale GERMANY = createConstant("de", "DE");
static public final Locale ITALY = createConstant("it", "IT");
static public final Locale JAPAN = createConstant("ja", "JP");
static public final Locale KOREA = createConstant("ko", "KR");
static public final Locale UK = createConstant("en", "GB");
static public final Locale US = createConstant("en", "US");
static public final Locale CANADA = createConstant("en", "CA");
static public final Locale CANADA_FRENCH = createConstant("fr", "CA");

java.time.DayOfWeek

public enum DayOfWeek implements TemporalAccessor, TemporalAdjuster {
    MONDAY,
    TUESDAY,
    WEDNESDAY,
    THURSDAY,
    FRIDAY,
    SATURDAY,
    SUNDAY;

java.time.Month

public enum Month implements TemporalAccessor, TemporalAdjuster {

    JANUARY,
    FEBRUARY,
    MARCH,
    APRIL,
    MAY,
    JUNE,
    JULY,
    AUGUST,
    SEPTEMBER,
    OCTOBER,
    NOVEMBER,
    DECEMBER;

java.math.BigInteger

public static final BigInteger ZERO = new BigInteger(new int[0], 0);
public static final BigInteger ONE = valueOf(1);
public static final BigInteger TEN = valueOf(10);

Apache commons-codec

org.apache.commons.codec.CharEncoding

public static final String ISO_8859_1 = "ISO-8859-1";
public static final String US_ASCII = "US-ASCII";
public static final String UTF_16 = "UTF-16";
public static final String UTF_16BE = "UTF-16BE";
public static final String UTF_16LE = "UTF-16LE";
public static final String UTF_8 = "UTF-8";

Apache Commons Lang3

org.apache.commons.lang3.StringUtils

public static final String SPACE = " ";
public static final String EMPTY = "";
public static final String LF = "\n";
public static final String CR = "\r";

org.apache.commons.lang3.BooleanUtils

public static final String FALSE = "false";
public static final String NO = "no";
public static final String OFF = "off";
public static final String ON = "on";
public static final String TRUE = "true";
public static final String YES = "yes";

org.apache.commons.lang3.math.NumberUtils

public static final Long LONG_ZERO = Long.valueOf(0L);
public static final Long LONG_ONE = Long.valueOf(1L);
public static final Long LONG_MINUS_ONE = Long.valueOf(-1L);
public static final Integer INTEGER_ZERO = Integer.valueOf(0);
public static final Integer INTEGER_ONE = Integer.valueOf(1);
public static final Integer INTEGER_TWO = Integer.valueOf(2);
public static final Integer INTEGER_MINUS_ONE = Integer.valueOf(-1);
public static final Short SHORT_ZERO = Short.valueOf((short) 0);
public static final Short SHORT_ONE = Short.valueOf((short) 1);
public static final Short SHORT_MINUS_ONE = Short.valueOf((short) -1);
public static final Byte BYTE_ZERO = Byte.valueOf((byte) 0);
public static final Byte BYTE_ONE = Byte.valueOf((byte) 1);
public static final Byte BYTE_MINUS_ONE = Byte.valueOf((byte) -1);
public static final Double DOUBLE_ZERO = Double.valueOf(0.0d);
public static final Double DOUBLE_ONE = Double.valueOf(1.0d);
public static final Double DOUBLE_MINUS_ONE = Double.valueOf(-1.0d);
public static final Float FLOAT_ZERO = Float.valueOf(0.0f);
public static final Float FLOAT_ONE = Float.valueOf(1.0f);
public static final Float FLOAT_MINUS_ONE = Float.valueOf(-1.0f);

org.apache.commons.lang3.time.DateUtils

public static final long MILLIS_PER_SECOND = 1000;
public static final long MILLIS_PER_MINUTE = 60 * MILLIS_P

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