Java 数据类型转换工具类
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.NumberFormat;
import java.text.ParseException;
/**
* A simple object converter
* 简单数据类型转换工具类
*/
public class Converter {
/**
* Gets a String from a Object in a null-safe manner.
* <p>
* The String is obtained via <code>toString</code>.
*
* @param obj the object to use
* @return the value of the Object as a String, <code>null</code> if null object input
*/
public static String getAsString(final Object obj) {
if (obj != null) {
return obj.toString();
}
return null;
}
/**
* Gets a String from a Object in a null-safe manner.
* <p>
* The String is obtained via <code>toString</code>.
*
* @param obj the object to use
* @param defaultValue what to return if the value is null or if the conversion fails
* @return the value of the Object as a String, <code>defaultValue</code> if null object input
*/
public static String getAsString(final Object obj, String defaultValue) {
String answer = getAsString(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a Number from a Object in a null-safe manner.
* <p>
* If the value is a <code>Number</code> it is returned directly.
* If the value is a <code>String</code> it is converted using
* {@link NumberFormat#parse(String)} on the system default formatter
* returning <code>null</code> if the conversion fails.
* Otherwise, <code>null</code> is returned.
*
* @param obj the object to use
* @return the value of the Object as a Number, <code>null</code> if null object input
*/
public static Number getAsNumber(final Object obj) {
if (obj != null) {
if (obj instanceof Number) {
return (Number) obj;
} else if (obj instanceof Boolean) {
Boolean flag = (Boolean) obj;
return flag ? 1 : 0;
} else if (obj instanceof String) {
try {
String text = (String) obj;
return NumberFormat.getInstance().parse(text);
} catch (ParseException e) {
// ignore exception
}
}
}
return null;
}
/**
* Converting the Object into a number,
* using the default value if the the conversion fails.
*
* @param obj the object to use
* @param defaultValue what to return if the value is null or if the conversion fails
* @return the value of the object as a number, or defaultValue if the
* original value is null, the object is null or the number conversion
* fails
*/
public static Number getAsNumber(final Object obj, Number defaultValue) {
Number answer = getAsNumber(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a Boolean from a Object in a null-safe manner.
* <p>
* If the value is a <code>Boolean</code> it is returned directly.
* If the value is a <code>String</code> and it equals 'true' ignoring case
* then <code>true</code> is returned, otherwise <code>false</code>.
* If the value is a <code>Number</code> an integer zero value returns
* <code>false</code> and non-zero returns <code>true</code>.
* Otherwise, <code>null</code> is returned.
*
* @param obj the object to use
* @return the value of the Object as a Boolean, <code>null</code> if null object input
*/
public static Boolean getAsBoolean(final Object obj) {
if (obj != null) {
if (obj instanceof Boolean) {
return (Boolean) obj;
} else if (obj instanceof String) {
return Boolean.valueOf((String) obj);
} else if (obj instanceof Number) {
Number n = (Number) obj;
return (n.intValue() != 0) ? Boolean.TRUE : Boolean.FALSE;
}
}
return null;
}
/**
* Gets a Boolean from a Object in a null-safe manner.
* <p>
* If the value is a <code>Boolean</code> it is returned directly.
* If the value is a <code>String</code> and it equals 'true' ignoring case
* then <code>true</code> is returned, otherwise <code>false</code>.
* If the value is a <code>Number</code> an integer zero value returns
* <code>false</code> and non-zero returns <code>true</code>.
* Otherwise, <code>null</code> is returned.
*
* @param obj the object to use
* @param defaultValue what to return if the value is null or if the conversion fails
* @return the value of the Object as a Boolean, <code>defaultValue</code> if null object input
*/
public static Boolean getAsBoolean(final Object obj, Boolean defaultValue) {
Boolean answer = getAsBoolean(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a boolean from a Object in a null-safe manner.
* <p>
* If the value is a <code>Boolean</code> its value is returned.
* If the value is a <code>String</code> and it equals 'true' ignoring case
* then <code>true</code> is returned, otherwise <code>false</code>.
* If the value is a <code>Number</code> an integer zero value returns
* <code>false</code> and non-zero returns <code>true</code>.
* Otherwise, <code>false</code> is returned.
*
* @param obj the object to use
* @return the value of the Object as a Boolean, <code>false</code> if null object input
*/
public static boolean getAsBooleanValue(final Object obj) {
Boolean booleanObject = getAsBoolean(obj);
if (booleanObject == null) {
return false;
}
return booleanObject.booleanValue();
}
/**
* Gets a boolean from a Object in a null-safe manner.
* <p>
* If the value is a <code>Boolean</code> its value is returned.
* If the value is a <code>String</code> and it equals 'true' ignoring case
* then <code>true</code> is returned, otherwise <code>false</code>.
* If the value is a <code>Number</code> an integer zero value returns
* <code>false</code> and non-zero returns <code>true</code>.
* Otherwise, <code>false</code> is returned.
*
* @param obj the object to use
* @param defaultValue what to return if the value is null or if the conversion fails
* @return the value in the Map as a Boolean, <code>defaultValue</code> if null object input
*/
public static boolean getAsBooleanValue(final Object obj, boolean defaultValue) {
Boolean booleanObject = getAsBoolean(obj);
if (booleanObject == null) {
return defaultValue;
}
return booleanObject.booleanValue();
}
/**
* Gets a Byte from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Byte is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of Object as a Byte, <code>null</code> if null object input
*/
public static Byte getAsByte(final Object obj) {
Number answer = getAsNumber(obj);
if (answer == null) {
return null;
} else if (answer instanceof Byte) {
return (Byte) answer;
}
return Byte.valueOf(answer.byteValue());
}
/**
* Gets a Byte from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Byte is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a Byte, <code>defaultValue</code> if null object input
*/
public static Byte getAsByte(final Object obj, Byte defaultValue) {
Byte answer = getAsByte(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a byte from a Object in a null-safe manner.
* <p>
* The byte is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a byte, <code>0</code> if null object input
*/
public static byte getAsByteValue(final Object obj) {
Byte byteObject = getAsByte(obj);
if (byteObject == null) {
return 0;
}
return byteObject.byteValue();
}
/**
* Gets a byte from a Object in a null-safe manner.
* <p>
* The byte is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of the Object as a byte, <code>defaultValue</code> if null object input
*/
public static byte getAsByteValue(final Object obj, byte defaultValue) {
Byte byteObject = getAsByte(obj);
if (byteObject == null) {
return defaultValue;
}
return byteObject.byteValue();
}
/**
* Gets a Short from a Object in a null-safe manner.
* <p>
* The Short is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a Short, <code>null</code> if null object input
*/
public static Short getAsShort(final Object obj) {
Number answer = getAsNumber(obj);
if (answer == null) {
return null;
} else if (answer instanceof Short) {
return (Short) answer;
}
return Short.valueOf(answer.shortValue());
}
/**
* Gets a Short from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Short is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a Short, <code>defaultValue</code> if null object input
*/
public static Short getAsShort(final Object obj, Short defaultValue) {
Short answer = getAsShort(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a short from a Object in a null-safe manner.
* <p>
* The short is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a short, <code>0</code> if null object input
*/
public static short getAsShortValue(final Object obj) {
Short shortObject = getAsShort(obj);
if (shortObject == null) {
return 0;
}
return shortObject.shortValue();
}
/**
* Gets a short from a Object in a null-safe manner.
* <p>
* The short is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of the Object as a short, <code>defaultValue</code> if null object input
*/
public static short getAsShortValue(final Object obj, short defaultValue) {
Short shortObject = getAsShort(obj);
if (shortObject == null) {
return defaultValue;
}
return shortObject.shortValue();
}
/**
* Gets a Integer from a Object in a null-safe manner.
* <p>
* The Integer is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a Integer, <code>null</code> if null object input
*/
public static Integer getAsInteger(final Object obj) {
Number answer = getAsNumber(obj);
if (answer == null) {
return null;
} else if (answer instanceof Integer) {
return (Integer) answer;
}
return Integer.valueOf(answer.intValue());
}
/**
* Gets a Integer from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Integer is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a Integer, <code>defaultValue</code> if null object input
*/
public static Integer getAsInteger(final Object obj, Integer defaultValue) {
Integer answer = getAsInteger(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a int from a Object in a null-safe manner.
* <p>
* The int is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a int, <code>0</code> if null object input
*/
public static int getAsIntValue(final Object obj) {
Integer integerObject = getAsInteger(obj);
if (integerObject == null) {
return 0;
}
return integerObject.intValue();
}
/**
* Gets a int from a Object in a null-safe manner.
* <p>
* The int is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of the Object as a int, <code>defaultValue</code> if null object input
*/
public static int getAsIntValue(final Object obj, int defaultValue) {
Integer integerObject = getAsInteger(obj);
if (integerObject == null) {
return defaultValue;
}
return integerObject.intValue();
}
/**
* Gets a Long from a Object in a null-safe manner.
* <p>
* The Long is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a Long, <code>null</code> if null object input
*/
public static Long getAsLong(final Object obj) {
Number answer = getAsNumber(obj);
if (answer == null) {
return null;
} else if (answer instanceof Long) {
return (Long) answer;
}
return Long.valueOf(answer.longValue());
}
/**
* Gets a Long from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Long is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a Long, <code>defaultValue</code> if null object input
*/
public static Long getAsLong(final Object obj, Long defaultValue) {
Long answer = getAsLong(obj);
if (answer == null) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a long from a Object in a null-safe manner.
* <p>
* The long is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a long, <code>0L</code> if null object input
*/
public static long getAsLongValue(final Object obj) {
Long longObject = getAsLong(obj);
if (longObject == null) {
return 0L;
}
return longObject.longValue();
}
/**
* Gets a long from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The long is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a long, <code>defaultValue</code> if null object input
*/
public static long getAsLongValue(final Object obj, long defaultValue) {
Long longObject = getAsLong(obj);
if (longObject == null) {
return defaultValue;
}
return longObject.longValue();
}
/**
* Gets a Float from a Object in a null-safe manner.
* <p>
* The Float is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a Float, <code>null</code> if null object input
*/
public static Float getAsFloat(final Object obj) {
Number answer = getAsNumber(obj);
if (answer == null) {
return null;
} else if (answer instanceof Float) {
return (Float) answer;
}
return Float.valueOf(answer.floatValue());
}
/**
* Gets a Float from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Float is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a Float, <code>defaultValue</code> if null object input
*/
public static Float getAsFloat(final Object obj, Float defaultValue) {
Float answer = getAsFloat(obj);
if ( answer == null ) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a float from a Object in a null-safe manner.
* <p>
* The float is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of Object as a float, <code>0.0F</code> if null object input
*/
public static float getAsFloatValue(final Object obj) {
Float floatObject = getAsFloat(obj);
if (floatObject == null) {
return 0f;
}
return floatObject.floatValue();
}
/**
* Gets a float from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The float is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a float, <code>defaultValue</code> if null object input
*/
public static float getAsFloatValue(final Object obj, float defaultValue) {
Float floatObject = getAsFloat(obj);
if (floatObject == null) {
return defaultValue;
}
return floatObject.floatValue();
}
/**
* Gets a Double from a Object in a null-safe manner.
* <p>
* The Double is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of the Object as a Double, <code>null</code> if null object input
*/
public static Double getAsDouble(final Object obj) {
Number answer = getAsNumber(obj);
if (answer == null) {
return null;
} else if (answer instanceof Double) {
return (Double) answer;
}
return Double.valueOf(answer.doubleValue());
}
/**
* Gets a Double from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The Double is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a Double, <code>defaultValue</code> if null object input
*/
public static Double getAsDouble(final Object obj, Double defaultValue) {
Double answer = getAsDouble(obj);
if ( answer == null ) {
answer = defaultValue;
}
return answer;
}
/**
* Gets a double from a Object in a null-safe manner.
* <p>
* The double is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of Object as a double, <code>0.0</code> if null object input
*/
public static double getAsDoubleValue(final Object obj) {
Double doubleObject = getAsDouble(obj);
if (doubleObject == null) {
return 0d;
}
return doubleObject.doubleValue();
}
/**
* Gets a double from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The double is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a double, <code>defaultValue</code> if null object input
*/
public static double getAsDoubleValue(final Object obj, double defaultValue) {
Double doubleObject = getAsDouble(obj);
if (doubleObject == null) {
return defaultValue;
}
return doubleObject.doubleValue();
}
/**
* Gets a BigInteger from a Object in a null-safe manner.
* <p>
* The BigInteger is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of Object as a BigInteger, <code>0</code> if null object input
*/
public static BigInteger getAsBigInteger(final Object obj) {
Long longObject = getAsLong(obj);
if (longObject == null) {
return BigInteger.ZERO;
}
return BigInteger.valueOf(longObject.longValue());
}
/**
* Gets a BigInteger from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The BigInteger is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a BigInteger, <code>defaultValue</code> if null object input
*/
public static BigInteger getAsBigInteger(final Object obj, BigInteger defaultValue) {
Long longObject = getAsLong(obj);
if (longObject == null) {
return defaultValue;
}
return BigInteger.valueOf(longObject.longValue());
}
/**
* Gets a BigDecimal from a Object in a null-safe manner.
* <p>
* The BigDecimal is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @return the value of Object as a BigDecimal, <code>0</code> if null object input
*/
public static BigDecimal getAsBigDecimal(final Object obj) {
Double doubleObject = getAsDouble(obj);
if (doubleObject == null) {
return BigDecimal.ZERO;
}
return BigDecimal.valueOf(doubleObject.doubleValue());
}
/**
* Gets a BigDecimal from a Object in a null-safe manner,
* using the default value if the the conversion fails.
* <p>
* The BigDecimal is obtained from the results of {@link #getAsNumber(Object)}.
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return the value of Object as a BigDecimal, <code>defaultValue</code> if null object input
*/
public static BigDecimal getAsBigDecimal(final Object obj, BigDecimal defaultValue) {
Double doubleObject = getAsDouble(obj);
if (doubleObject == null) {
return defaultValue;
}
return BigDecimal.valueOf(doubleObject.doubleValue());
}
/**
*
*
* @param obj the object to use
* @param clz the type for conversion
* @return
*/
@SuppressWarnings("unchecked")
public static <R> R cast(final Object obj, final Class<R> clz) {
R result = null;
if (Boolean.class.equals(clz) || boolean.class.equals(clz)) {
result = (R) getAsBoolean(obj);
} else if (Byte.class.equals(clz) || byte.class.equals(clz)) {
result = (R) getAsByte(obj);
} else if (Short.class.equals(clz) || short.class.equals(clz)) {
result = (R) getAsShort(obj);
} else if (Integer.class.equals(clz) || int.class.equals(clz)) {
result = (R) getAsInteger(obj);
} else if (Long.class.equals(clz) || long.class.equals(clz)) {
result = (R) getAsLong(obj);
} else if (Float.class.equals(clz) || float.class.equals(clz)) {
result = (R) getAsFloat(obj);
} else if (Double.class.equals(clz) || double.class.equals(clz)) {
result = (R) getAsDouble(obj);
} else if (BigInteger.class.equals(clz)) {
result = (R) getAsBigInteger(obj);
} else if (BigDecimal.class.equals(clz)) {
result = (R) getAsBigDecimal(obj);
} else if (String.class.equals(clz)) {
result = (R) getAsString(obj);
}
return result;
}
/**
*
*
* @param obj the object to use
* @param defaultValue return if the value is null or if the conversion fails
* @return
*/
@SuppressWarnings("unchecked")
public static <R> R cast(final Object obj, R defaultValue) {
R result = null;
if (defaultValue == null) { return result; }
Class<?> clz = defaultValue.getClass();
if (Boolean.class.equals(clz) || boolean.class.equals(clz)) {
result = (R) getAsBoolean(obj, (Boolean) defaultValue);
} else if (Byte.class.equals(clz) || byte.class.equals(clz)) {
result = (R) getAsByte(obj, (Byte) defaultValue);
} else if (Short.class.equals(clz) || short.class.equals(clz)) {
result = (R) getAsShort(obj, (Short) defaultValue);
} else if (Integer.class.equals(clz) || int.class.equals(clz)) {
result = (R) getAsInteger(obj, (Integer) defaultValue);
} else if (Long.class.equals(clz) || long.class.equals(clz)) {
result = (R) getAsLong(obj, (Long) defaultValue);
} else if (Float.class.equals(clz) || float.class.equals(clz)) {
result = (R) getAsFloat(obj, (Float) defaultValue);
} else if (Double.class.equals(clz) || double.class.equals(clz)) {
result = (R) getAsDouble(obj, (Double) defaultValue);
} else if (BigInteger.class.equals(clz)) {
result = (R) getAsBigInteger(obj, (BigInteger) defaultValue);
} else if (BigDecimal.class.equals(clz)) {
result = (R) getAsBigDecimal(obj, (BigDecimal) defaultValue);
} else if (String.class.equals(clz)) {
result = (R) getAsString(obj, (String) defaultValue);
}
return result;
}
}