Java中的equals

Object:

public boolean equals(Object obj) {
        return (this == obj);
    }

1.Boolean:

public boolean equals(Object obj) {
        if (obj instanceof Boolean) {
            return value == ((Boolean)obj).booleanValue();
        }
        return false;
    }

2.String

public boolean equals(Object anObject) {
        if (this == anObject) {
            return true;
        }
        if (anObject instanceof String) {
            String anotherString = (String)anObject;
            int n = value.length;
            if (n == anotherString.value.length) {
                char v1[] = value;
                char v2[] = anotherString.value;
                int i = 0;
                while (n-- != 0) {
                    if (v1[i] != v2[i])
                        return false;
                    i++;
                }
                return true;
            }
        }
        return false;
    }

引用相同或者是String类型的相同的字符序列

3.Integer

public boolean equals(Object obj) {
        if (obj instanceof Integer) {
            return value == ((Integer)obj).intValue();
        }
        return false;
    }

4.Float

public boolean equals(Object obj) {
        return (obj instanceof Float)
               && (floatToIntBits(((Float)obj).value) == floatToIntBits(value));
    }

5.Double

public boolean equals(Object obj) {
        return (obj instanceof Double)
               && (doubleToLongBits(((Double)obj).value) ==
                      doubleToLongBits(value));
    }

6.Character

public boolean equals(Object obj) {
        if (obj instanceof Character) {
            return value == ((Character)obj).charValue();
        }
        return false;
    }

7.Short

public boolean equals(Object obj) {
        if (obj instanceof Short) {
            return value == ((Short)obj).shortValue();
        }
        return false;
    }

8.Byte

public boolean equals(Object obj) {
        if (obj instanceof Byte) {
            return value == ((Byte)obj).byteValue();
        }
        return false;
    }