org.springframework.expression.spel.standard

类 SpelExpression

java.lang.Object

org.springframework.expression.spel.standard.SpelExpression

所有已实现的接口:

Expression

public class SpelExpression
extends Object
implements Expression

A SpelExpression represents a parsed (valid) expression that is ready to be evaluated in a specified context. An expression can be evaluated standalone or in a specified context. During expression evaluation the context may be asked to resolve references to types, beans, properties, and methods.

从以下版本开始:

3.0

作者:

Andy Clement, Juergen Hoeller

构造器概要

构造器

构造器和说明
SpelExpression(String expression, SpelNodeImpl ast, SpelParserConfiguration configuration) Construct an expression, only used by the parser.

方法概要

限定符和类型	方法和说明
boolean	compileExpression() Perform expression compilation.
SpelNode	getAST() Return the Abstract Syntax Tree for the expression.
EvaluationContext	getEvaluationContext() Return the default evaluation context that will be used if none is supplied on an evaluation call.
String	getExpressionString() Return the original string used to create this expression (unmodified).
Object	getValue() Evaluate this expression in the default standard context.
<T> T	getValue(Class<T> expectedResultType) Evaluate the expression in the default context.
Object	getValue(EvaluationContext context) Evaluate this expression in the provided context and return the result of evaluation.
<T> T	getValue(EvaluationContext context, Class<T> expectedResultType) Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc.
Object	getValue(EvaluationContext context, Object rootObject) Evaluate this expression in the provided context and return the result of evaluation, but use the supplied root context as an override for any default root object specified in the context.
<T> T	getValue(EvaluationContext context, Object rootObject, Class<T> expectedResultType) Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc.
Object	getValue(Object rootObject) Evaluate this expression against the specified root object.
<T> T	getValue(Object rootObject, Class<T> expectedResultType) Evaluate the expression in the default context against the specified root object.
Class<?>	getValueType() Return the most general type that can be passed to a Expression.setValue(java.lang.Object, java.lang.Object) method using the default context.
Class<?>	getValueType(EvaluationContext context) Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.
Class<?>	getValueType(EvaluationContext context, Object rootObject) Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object, Object) method for the given context.
Class<?>	getValueType(Object rootObject) Return the most general type that can be passed to the Expression.setValue(Object, Object) method using the default context.
org.springframework.core.convert.TypeDescriptor	getValueTypeDescriptor() Return the most general type that can be passed to a Expression.setValue(java.lang.Object, java.lang.Object) method using the default context.
org.springframework.core.convert.TypeDescriptor	getValueTypeDescriptor(EvaluationContext context) Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.
org.springframework.core.convert.TypeDescriptor	getValueTypeDescriptor(EvaluationContext context, Object rootObject) Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object, Object) method for the given context.
org.springframework.core.convert.TypeDescriptor	getValueTypeDescriptor(Object rootObject) Return the most general type that can be passed to the Expression.setValue(Object, Object) method using the default context.
boolean	isWritable(EvaluationContext context) Determine if an expression can be written to, i.e. setValue() can be called.
boolean	isWritable(EvaluationContext context, Object rootObject) Determine if an expression can be written to, i.e. setValue() can be called.
boolean	isWritable(Object rootObject) Determine if an expression can be written to, i.e. setValue() can be called.
void	revertToInterpreted() Cause an expression to revert to being interpreted if it has been using a compiled form.
void	setEvaluationContext(EvaluationContext evaluationContext) Set the evaluation context that will be used if none is specified on an evaluation call.
void	setValue(EvaluationContext context, Object value) Set this expression in the provided context to the value provided.
void	setValue(EvaluationContext context, Object rootObject, Object value) Set this expression in the provided context to the value provided.
void	setValue(Object rootObject, Object value) Set this expression in the provided context to the value provided.
String	toStringAST() Produce a string representation of the Abstract Syntax Tree for the expression.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

SpelExpression

public SpelExpression(String expression,
                      SpelNodeImpl ast,
                      SpelParserConfiguration configuration)

Construct an expression, only used by the parser.

方法详细资料

setEvaluationContext

public void setEvaluationContext(EvaluationContext evaluationContext)

Set the evaluation context that will be used if none is specified on an evaluation call.

参数:

evaluationContext - the evaluation context to use

getEvaluationContext

public EvaluationContext getEvaluationContext()

Return the default evaluation context that will be used if none is supplied on an evaluation call.

返回:

the default evaluation context

getExpressionString

public String getExpressionString()

从接口复制的说明: Expression

Return the original string used to create this expression (unmodified).

指定者:

getExpressionString 在接口中 Expression

返回:

the original expression string

getValue

@Nullable
public Object getValue()
                           throws EvaluationException

从接口复制的说明: Expression

Evaluate this expression in the default standard context.

指定者:

getValue 在接口中 Expression

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public <T> T getValue(@Nullable
                                 Class<T> expectedResultType)
                          throws EvaluationException

从接口复制的说明: Expression

Evaluate the expression in the default context. If the result of the evaluation does not match (and cannot be converted to) the expected result type then an exception will be returned.

指定者:

getValue 在接口中 Expression

参数:

expectedResultType - the class the caller would like the result to be

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public Object getValue(Object rootObject)
                           throws EvaluationException

从接口复制的说明: Expression

Evaluate this expression against the specified root object.

指定者:

getValue 在接口中 Expression

参数:

rootObject - the root object against which to evaluate the expression

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public <T> T getValue(Object rootObject,
                                 @Nullable
                                 Class<T> expectedResultType)
                          throws EvaluationException

从接口复制的说明: Expression

Evaluate the expression in the default context against the specified root object. If the result of the evaluation does not match (and cannot be converted to) the expected result type then an exception will be returned.

指定者:

getValue 在接口中 Expression

参数:

rootObject - the root object against which to evaluate the expression

expectedResultType - the class the caller would like the result to be

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public Object getValue(EvaluationContext context)
                           throws EvaluationException

从接口复制的说明: Expression

Evaluate this expression in the provided context and return the result of evaluation.

指定者:

getValue 在接口中 Expression

参数:

context - the context in which to evaluate the expression

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public <T> T getValue(EvaluationContext context,
                                 @Nullable
                                 Class<T> expectedResultType)
                          throws EvaluationException

从接口复制的说明: Expression

Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc. The type of the evaluation result is expected to be of a particular class and an exception will be thrown if it is not and cannot be converted to that type.

指定者:

getValue 在接口中 Expression

参数:

context - the context in which to evaluate the expression

expectedResultType - the class the caller would like the result to be

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public Object getValue(EvaluationContext context,
                                  Object rootObject)
                           throws EvaluationException

从接口复制的说明: Expression

Evaluate this expression in the provided context and return the result of evaluation, but use the supplied root context as an override for any default root object specified in the context.

指定者:

getValue 在接口中 Expression

参数:

context - the context in which to evaluate the expression

rootObject - the root object against which to evaluate the expression

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValue

@Nullable
public <T> T getValue(EvaluationContext context,
                                 Object rootObject,
                                 @Nullable
                                 Class<T> expectedResultType)
                          throws EvaluationException

从接口复制的说明: Expression

Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc. The type of the evaluation result is expected to be of a particular class and an exception will be thrown if it is not and cannot be converted to that type. The supplied root object overrides any default specified on the supplied context.

指定者:

getValue 在接口中 Expression

参数:

context - the context in which to evaluate the expression

rootObject - the root object against which to evaluate the expression

expectedResultType - the class the caller would like the result to be

返回:

the evaluation result

抛出:

EvaluationException - if there is a problem during evaluation

getValueType

@Nullable
public Class<?> getValueType()
                                 throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to a Expression.setValue(java.lang.Object, java.lang.Object) method using the default context.

指定者:

getValueType 在接口中 Expression

返回:

the most general type of value that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueType

@Nullable
public Class<?> getValueType(Object rootObject)
                                 throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to the Expression.setValue(Object, Object) method using the default context.

指定者:

getValueType 在接口中 Expression

参数:

rootObject - the root object against which to evaluate the expression

返回:

the most general type of value that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueType

@Nullable
public Class<?> getValueType(EvaluationContext context)
                                 throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.

指定者:

getValueType 在接口中 Expression

参数:

context - the context in which to evaluate the expression

返回:

the most general type of value that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueType

@Nullable
public Class<?> getValueType(EvaluationContext context,
                                        Object rootObject)
                                 throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object, Object) method for the given context. The supplied root object overrides any specified in the context.

指定者:

getValueType 在接口中 Expression

参数:

context - the context in which to evaluate the expression

rootObject - the root object against which to evaluate the expression

返回:

the most general type of value that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueTypeDescriptor

@Nullable
public org.springframework.core.convert.TypeDescriptor getValueTypeDescriptor()
                                                                                  throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to a Expression.setValue(java.lang.Object, java.lang.Object) method using the default context.

指定者:

getValueTypeDescriptor 在接口中 Expression

返回:

a type descriptor for values that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueTypeDescriptor

@Nullable
public org.springframework.core.convert.TypeDescriptor getValueTypeDescriptor(Object rootObject)
                                                                                  throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to the Expression.setValue(Object, Object) method using the default context.

指定者:

getValueTypeDescriptor 在接口中 Expression

参数:

rootObject - the root object against which to evaluate the expression

返回:

a type descriptor for values that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueTypeDescriptor

@Nullable
public org.springframework.core.convert.TypeDescriptor getValueTypeDescriptor(EvaluationContext context)
                                                                                  throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object) method for the given context.

指定者:

getValueTypeDescriptor 在接口中 Expression

参数:

context - the context in which to evaluate the expression

返回:

a type descriptor for values that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

getValueTypeDescriptor

@Nullable
public org.springframework.core.convert.TypeDescriptor getValueTypeDescriptor(EvaluationContext context,
                                                                                         Object rootObject)
                                                                                  throws EvaluationException

从接口复制的说明: Expression

Return the most general type that can be passed to the Expression.setValue(EvaluationContext, Object, Object) method for the given context. The supplied root object overrides any specified in the context.

指定者:

getValueTypeDescriptor 在接口中 Expression

参数:

context - the context in which to evaluate the expression

rootObject - the root object against which to evaluate the expression

返回:

a type descriptor for values that can be set on this context

抛出:

EvaluationException - if there is a problem determining the type

isWritable

public boolean isWritable(Object rootObject)
                   throws EvaluationException

从接口复制的说明: Expression

Determine if an expression can be written to, i.e. setValue() can be called.

指定者:

isWritable 在接口中 Expression

参数:

rootObject - the root object against which to evaluate the expression

返回:

true if the expression is writable; false otherwise

抛出:

EvaluationException - if there is a problem determining if it is writable

isWritable

public boolean isWritable(EvaluationContext context)
                   throws EvaluationException

从接口复制的说明: Expression

Determine if an expression can be written to, i.e. setValue() can be called.

指定者:

isWritable 在接口中 Expression

参数:

context - the context in which the expression should be checked

返回:

true if the expression is writable; false otherwise

抛出:

EvaluationException - if there is a problem determining if it is writable

isWritable

public boolean isWritable(EvaluationContext context,
                          Object rootObject)
                   throws EvaluationException

从接口复制的说明: Expression

Determine if an expression can be written to, i.e. setValue() can be called. The supplied root object overrides any specified in the context.

指定者:

isWritable 在接口中 Expression

参数:

context - the context in which the expression should be checked

rootObject - the root object against which to evaluate the expression

返回:

true if the expression is writable; false otherwise

抛出:

EvaluationException - if there is a problem determining if it is writable

setValue

public void setValue(Object rootObject,
                     @Nullable
                     Object value)
              throws EvaluationException

从接口复制的说明: Expression

Set this expression in the provided context to the value provided.

指定者:

setValue 在接口中 Expression

参数:

rootObject - the root object against which to evaluate the expression

value - the new value

抛出:

EvaluationException - if there is a problem during evaluation

setValue

public void setValue(EvaluationContext context,
                     @Nullable
                     Object value)
              throws EvaluationException

从接口复制的说明: Expression

Set this expression in the provided context to the value provided.

指定者:

setValue 在接口中 Expression

参数:

context - the context in which to set the value of the expression

value - the new value

抛出:

EvaluationException - if there is a problem during evaluation

setValue

public void setValue(EvaluationContext context,
                     Object rootObject,
                     @Nullable
                     Object value)
              throws EvaluationException

从接口复制的说明: Expression

Set this expression in the provided context to the value provided. The supplied root object overrides any specified in the context.

指定者:

setValue 在接口中 Expression

参数:

context - the context in which to set the value of the expression

rootObject - the root object against which to evaluate the expression

value - the new value

抛出:

EvaluationException - if there is a problem during evaluation

compileExpression

public boolean compileExpression()

Perform expression compilation. This will only succeed once exit descriptors for all nodes have been determined. If the compilation fails and has failed more than 100 times the expression is no longer considered suitable for compilation.

revertToInterpreted

public void revertToInterpreted()

Cause an expression to revert to being interpreted if it has been using a compiled form. It also resets the compilation attempt failure count (an expression is normally no longer considered compilable if it cannot be compiled after 100 attempts).

getAST

public SpelNode getAST()

Return the Abstract Syntax Tree for the expression.

toStringAST

public String toStringAST()

Produce a string representation of the Abstract Syntax Tree for the expression. This should ideally look like the input expression, but properly formatted since any unnecessary whitespace will have been discarded during the parse of the expression.

返回:

the string representation of the AST