public class EqualsBuilder extends Object implements Builder<Boolean>
Object.equals(Object)
方法的构建器
两个对象equals必须保证hashCode值相等,hashCode值相等不能保证一定equals
使用方法如下:
public boolean equals(Object obj) { if (obj == null) { return false; } if (obj == this) { return true; } if (obj.getClass() != getClass()) { return false; } MyClass rhs = (MyClass) obj; return new EqualsBuilder() .appendSuper(super.equals(obj)) .append(field1, rhs.field1) .append(field2, rhs.field2) .append(field3, rhs.field3) .isEquals(); }
我们也可以通过反射判断所有字段是否equals:
public boolean equals(Object obj) { return EqualsBuilder.reflectionEquals(this, obj); }
来自Apache Commons Lang改造
Constructor and Description |
---|
EqualsBuilder()
构造,初始状态值为true
|
Modifier and Type | Method and Description |
---|---|
EqualsBuilder |
append(boolean lhs,
boolean rhs)
Test if two
booleans s are equal. |
EqualsBuilder |
append(byte lhs,
byte rhs)
Test if two
byte s are equal. |
EqualsBuilder |
append(char lhs,
char rhs)
Test if two
char s are equal. |
EqualsBuilder |
append(double lhs,
double rhs)
Test if two
double s are equal by testing that the
pattern of bits returned by doubleToLong are equal. |
EqualsBuilder |
append(float lhs,
float rhs)
Test if two
float s are equal byt testing that the
pattern of bits returned by doubleToLong are equal. |
EqualsBuilder |
append(int lhs,
int rhs)
Test if two
int s are equal. |
EqualsBuilder |
append(long lhs,
long rhs)
Test if two
long s are equal. |
EqualsBuilder |
append(Object lhs,
Object rhs)
Test if two
Object s are equal using their
equals method. |
EqualsBuilder |
append(short lhs,
short rhs)
Test if two
short s are equal. |
EqualsBuilder |
appendSuper(boolean superEquals)
Adds the result of
super.equals() to this builder. |
Boolean |
build()
Returns
true if the fields that have been checked
are all equal. |
boolean |
isEquals()
Returns
true if the fields that have been checked
are all equal. |
static boolean |
reflectionEquals(Object lhs,
Object rhs,
boolean testTransients)
This method uses reflection to determine if the two
Object s
are equal. |
static boolean |
reflectionEquals(Object lhs,
Object rhs,
boolean testTransients,
Class<?> reflectUpToClass,
String... excludeFields)
This method uses reflection to determine if the two
Object s
are equal. |
static boolean |
reflectionEquals(Object lhs,
Object rhs,
Collection<String> excludeFields)
反射检查两个对象是否equals,此方法检查对象及其父对象的属性(包括私有属性)是否equals
|
static boolean |
reflectionEquals(Object lhs,
Object rhs,
String... excludeFields)
反射检查两个对象是否equals,此方法检查对象及其父对象的属性(包括私有属性)是否equals
|
void |
reset()
Reset the EqualsBuilder so you can use the same object again
|
protected EqualsBuilder |
setEquals(boolean isEquals)
Sets the
isEquals value. |
public static boolean reflectionEquals(Object lhs, Object rhs, Collection<String> excludeFields)
反射检查两个对象是否equals,此方法检查对象及其父对象的属性(包括私有属性)是否equals
lhs
- 此对象rhs
- 另一个对象excludeFields
- 排除的字段集合,如果有不参与计算equals的字段加入此集合即可true
public static boolean reflectionEquals(Object lhs, Object rhs, String... excludeFields)
反射检查两个对象是否equals,此方法检查对象及其父对象的属性(包括私有属性)是否equals
lhs
- 此对象rhs
- 另一个对象excludeFields
- 排除的字段集合,如果有不参与计算equals的字段加入此集合即可true
public static boolean reflectionEquals(Object lhs, Object rhs, boolean testTransients)
This method uses reflection to determine if the two Object
s
are equal.
It uses AccessibleObject.setAccessible
to gain access to private
fields. This means that it will throw a security exception if run under
a security manager, if the permissions are not set up correctly. It is also
not as efficient as testing explicitly. Non-primitive fields are compared using
equals()
.
If the TestTransients parameter is set to true
, transient
members will be tested, otherwise they are ignored, as they are likely
derived fields, and not part of the value of the Object
.
Static fields will not be tested. Superclass fields will be included.
lhs
- this
objectrhs
- the other objecttestTransients
- whether to include transient fieldstrue
if the two Objects have tested equals.public static boolean reflectionEquals(Object lhs, Object rhs, boolean testTransients, Class<?> reflectUpToClass, String... excludeFields)
This method uses reflection to determine if the two Object
s
are equal.
It uses AccessibleObject.setAccessible
to gain access to private
fields. This means that it will throw a security exception if run under
a security manager, if the permissions are not set up correctly. It is also
not as efficient as testing explicitly. Non-primitive fields are compared using
equals()
.
If the testTransients parameter is set to true
, transient
members will be tested, otherwise they are ignored, as they are likely
derived fields, and not part of the value of the Object
.
Static fields will not be included. Superclass fields will be appended up to and including the specified superclass. A null superclass is treated as java.lang.Object.
lhs
- this
objectrhs
- the other objecttestTransients
- whether to include transient fieldsreflectUpToClass
- the superclass to reflect up to (inclusive),
may be null
excludeFields
- array of field names to exclude from testingtrue
if the two Objects have tested equals.public EqualsBuilder appendSuper(boolean superEquals)
Adds the result of super.equals()
to this builder.
superEquals
- the result of calling super.equals()
public EqualsBuilder append(Object lhs, Object rhs)
Test if two Object
s are equal using their
equals
method.
lhs
- the left hand objectrhs
- the right hand objectpublic EqualsBuilder append(long lhs, long rhs)
Test if two long
s are equal.
lhs
- the left hand long
rhs
- the right hand long
public EqualsBuilder append(int lhs, int rhs)
Test if two int
s are equal.
lhs
- the left hand int
rhs
- the right hand int
public EqualsBuilder append(short lhs, short rhs)
Test if two short
s are equal.
lhs
- the left hand short
rhs
- the right hand short
public EqualsBuilder append(char lhs, char rhs)
Test if two char
s are equal.
lhs
- the left hand char
rhs
- the right hand char
public EqualsBuilder append(byte lhs, byte rhs)
Test if two byte
s are equal.
lhs
- the left hand byte
rhs
- the right hand byte
public EqualsBuilder append(double lhs, double rhs)
Test if two double
s are equal by testing that the
pattern of bits returned by doubleToLong
are equal.
This handles NaNs, Infinities, and -0.0
.
It is compatible with the hash code generated by
HashCodeBuilder
.
lhs
- the left hand double
rhs
- the right hand double
public EqualsBuilder append(float lhs, float rhs)
Test if two float
s are equal byt testing that the
pattern of bits returned by doubleToLong are equal.
This handles NaNs, Infinities, and -0.0
.
It is compatible with the hash code generated by
HashCodeBuilder
.
lhs
- the left hand float
rhs
- the right hand float
public EqualsBuilder append(boolean lhs, boolean rhs)
Test if two booleans
s are equal.
lhs
- the left hand boolean
rhs
- the right hand boolean
public boolean isEquals()
Returns true
if the fields that have been checked
are all equal.
public Boolean build()
Returns true
if the fields that have been checked
are all equal.
protected EqualsBuilder setEquals(boolean isEquals)
isEquals
value.isEquals
- The value to set.public void reset()
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