本文主要是介绍接口 ValueStack：com.opensymphony.xwork2.util，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

方法概要

方法
限定符和类型	方法和说明
`java.lang.String`	`findString(java.lang.String expr)`
`java.lang.String`	`findString(java.lang.String expr, boolean throwExceptionOnFailure)`
`java.lang.Object`	`findValue(java.lang.String expr)` Find a value by evaluating the given expression against the stack in the default search order.
`java.lang.Object`	`findValue(java.lang.String expr, boolean throwExceptionOnFailure)`
`java.lang.Object`	`findValue(java.lang.String expr, java.lang.Class asType)` Find a value by evaluating the given expression against the stack in the default search order.
`java.lang.Object`	`findValue(java.lang.String expr, java.lang.Class asType, boolean throwExceptionOnFailure)`
`java.util.Map<java.lang.String,java.lang.Object>`	`getContext()` Gets the context for this value stack.
`java.util.Map<java.lang.Object,java.lang.Object>`	`getExprOverrides()` Gets the override map if anyone exists.
`CompoundRoot`	`getRoot()` Get the CompoundRoot which holds the objects pushed onto the stack
`java.lang.Object`	`peek()` Get the object on the top of the stack without changing the stack.
`java.lang.Object`	`pop()` Get the object on the top of the stack and remove it from the stack.
`void`	`push(java.lang.Object o)` Put this object onto the top of the stack
`void`	`set(java.lang.String key, java.lang.Object o)` Sets an object on the stack with the given key so it is retrievable by `findValue(String)`, `findValue(String, Class)`
`void`	`setDefaultType(java.lang.Class defaultType)` Sets the default type to convert to if no type is provided when getting a value.
`void`	`setExprOverrides(java.util.Map<java.lang.Object,java.lang.Object> overrides)` Set a override map containing `key -> values` that takes precedent when doing find operations on the ValueStack.
`void`	`setValue(java.lang.String expr, java.lang.Object value)` Attempts to set a property on a bean in the stack with the given expression using the default search order.
`void`	`setValue(java.lang.String expr, java.lang.Object value, boolean throwExceptionOnFailure)` Attempts to set a property on a bean in the stack with the given expression using the default search order.
`int`	`size()` Get the number of objects in the stack

- 字段详细资料
  - VALUE_STACK
```
static final java.lang.String VALUE_STACK
```
    另请参阅:
    常量字段值
  - REPORT_ERRORS_ON_NO_PROP
```
static final java.lang.String REPORT_ERRORS_ON_NO_PROP
```
    另请参阅:
    常量字段值
- 方法详细资料
  - getContext
```
java.util.Map<java.lang.String,java.lang.Object> getContext()
```
    Gets the context for this value stack. The context holds all the information in the value stack and it's surroundings.
    
    返回:
    the context.
  - setDefaultType
```
void setDefaultType(java.lang.Class defaultType)
```
    Sets the default type to convert to if no type is provided when getting a value.
    
    参数:
    defaultType - the new default type
  - setExprOverrides
```
void setExprOverrides(java.util.Map<java.lang.Object,java.lang.Object> overrides)
```
    Set a override map containing key -> values that takes precedent when doing find operations on the ValueStack.
    See the unit test for ValueStackTest for examples.
    
    参数:
    overrides - overrides map.
  - getExprOverrides
```
java.util.Map<java.lang.Object,java.lang.Object> getExprOverrides()
```
    Gets the override map if anyone exists.
    
    返回:
    the override map, null if not set.
  - getRoot
```
CompoundRoot getRoot()
```
    Get the CompoundRoot which holds the objects pushed onto the stack
    
    返回:
    the root
  - setValue
```
void setValue(java.lang.String expr,java.lang.Object value)
```
    Attempts to set a property on a bean in the stack with the given expression using the default search order.
    
    参数:
    expr - the expression defining the path to the property to be set.
    
    value - the value to be set into the named property
  - setValue
```
void setValue(java.lang.String expr,java.lang.Object value,boolean throwExceptionOnFailure)
```
    Attempts to set a property on a bean in the stack with the given expression using the default search order.
    
    参数:
    expr - the expression defining the path to the property to be set.
    
    value - the value to be set into the named property
    
    throwExceptionOnFailure - a flag to tell whether an exception should be thrown if there is no property with the given name.
  - findString
```
java.lang.String findString(java.lang.String expr)
```
  - findString
```
java.lang.String findString(java.lang.String expr,boolean throwExceptionOnFailure)
```
  - findValue
```
java.lang.Object findValue(java.lang.String expr)
```
    Find a value by evaluating the given expression against the stack in the default search order.
    
    参数:
    expr - the expression giving the path of properties to navigate to find the property value to return
    返回:
    the result of evaluating the expression
  - findValue
```
java.lang.Object findValue(java.lang.String expr,boolean throwExceptionOnFailure)
```
  - findValue
```
java.lang.Object findValue(java.lang.String expr,java.lang.Class asType)
```
    Find a value by evaluating the given expression against the stack in the default search order.
    
    参数:
    expr - the expression giving the path of properties to navigate to find the property value to return
    
    asType - the type to convert the return value to
    返回:
    the result of evaluating the expression
  - findValue
```
java.lang.Object findValue(java.lang.String expr,java.lang.Class asType,boolean throwExceptionOnFailure)
```
  - peek
```
java.lang.Object peek()
```
    Get the object on the top of the stack without changing the stack.
    
    返回:
    the object on the top.
    另请参阅:
    CompoundRoot.peek()
  - pop
```
java.lang.Object pop()
```
    Get the object on the top of the stack and remove it from the stack.
    
    返回:
    the object on the top of the stack
    另请参阅:
    CompoundRoot.pop()
  - push
```
void push(java.lang.Object o)
```
    Put this object onto the top of the stack
    
    参数:
    o - the object to be pushed onto the stack
    另请参阅:
    CompoundRoot.push(Object)
  - set
```
void set(java.lang.String key,java.lang.Object o)
```
    Sets an object on the stack with the given key so it is retrievable by findValue(String), findValue(String, Class)
    
    参数:
    key - the key
    
    o - the object
  - size
```
int size()
```
    Get the number of objects in the stack
    
    返回:
    the number of objects in the stack