java.lang.Object
- java.util.AbstractMap<K,V>
- - java.util.HashMap<String,Object>
  - - org.springframework.web.servlet.FlashMap

所有已实现的接口:
Serializable, Cloneable, Comparable<FlashMap>, Map<String,Object>
```
public final class FlashMap
extends HashMap<String,Object>
implements Comparable<FlashMap>
```
A FlashMap provides a way for one request to store attributes intended for use in another. This is most commonly needed when redirecting from one URL to another -- e.g. the Post/Redirect/Get pattern. A FlashMap is saved before the redirect (typically in the session) and is made available after the redirect and removed immediately.
A FlashMap can be set up with a request path and request parameters to help identify the target request. Without this information, a FlashMap is made available to the next request, which may or may not be the intended recipient. On a redirect, the target URL is known and a FlashMap can be updated with that information. This is done automatically when the org.springframework.web.servlet.view.RedirectView is used.
Note: annotated controllers will usually not use FlashMap directly. See org.springframework.web.servlet.mvc.support.RedirectAttributes for an overview of using flash attributes in annotated controllers.
从以下版本开始:
3.1
作者:
Rossen Stoyanchev
另请参阅:
FlashMapManager, 序列化表格

嵌套类概要
- 从类继承的嵌套类/接口 java.util.AbstractMap
  AbstractMap.SimpleEntry<K extends Object,V extends Object>, AbstractMap.SimpleImmutableEntry<K extends Object,V extends Object>
- 从接口继承的嵌套类/接口 java.util.Map
  Map.Entry<K extends Object,V extends Object>

构造器概要
构造器
构造器说明
FlashMap()

方法概要

所有方法实例方法具体方法
修饰符和类型	方法	说明
`FlashMap`	`addTargetRequestParam(String name, String value)`	Provide a request parameter identifying the request for this FlashMap.
`FlashMap`	`addTargetRequestParams(MultiValueMap<String,String> params)`	Provide request parameters identifying the request for this FlashMap.
`int`	`compareTo(FlashMap other)`	Compare two FlashMaps and prefer the one that specifies a target URL path or has more target URL parameters.
`boolean`	`equals(Object other)`
`long`	`getExpirationTime()`	Return the expiration time for the FlashMap or -1 if the expiration period has not started.
`MultiValueMap<String,String>`	`getTargetRequestParams()`	Return the parameters identifying the target request, or an empty map.
`String`	`getTargetRequestPath()`	Return the target URL path (or `null` if none specified).
`int`	`hashCode()`
`boolean`	`isExpired()`	Return whether this instance has expired depending on the amount of elapsed time since the call to `startExpirationPeriod(int)`.
`void`	`setExpirationTime(long expirationTime)`	Set the expiration time for the FlashMap.
`void`	`setTargetRequestPath(String path)`	Provide a URL path to help identify the target request for this FlashMap.
`void`	`startExpirationPeriod(int timeToLive)`	Start the expiration period for this instance.
`String`	`toString()`

从类继承的方法 java.util.HashMap
clear, clone, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, forEach, get, getOrDefault, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

从类继承的方法 java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- 构造器详细资料
  - FlashMap
```
public FlashMap()
```
- 方法详细资料
  - setTargetRequestPath
```
public void setTargetRequestPath(@Nullable
                                 String path)
```
    Provide a URL path to help identify the target request for this FlashMap.
    The path may be absolute (e.g. "/application/resource") or relative to the current request (e.g. "../resource").
  - getTargetRequestPath
```
@Nullable
public String getTargetRequestPath()
```
    Return the target URL path (or null if none specified).
  - addTargetRequestParams
```
public FlashMap addTargetRequestParams(@Nullable
                                       MultiValueMap<String,String> params)
```
    Provide request parameters identifying the request for this FlashMap.
    参数:
    params - a Map with the names and values of expected parameters
  - addTargetRequestParam
```
public FlashMap addTargetRequestParam(String name,
                                      String value)
```
    Provide a request parameter identifying the request for this FlashMap.
    参数:
    name - the expected parameter name (skipped if empty)
    value - the expected value (skipped if empty)
  - getTargetRequestParams
```
public MultiValueMap<String,String> getTargetRequestParams()
```
    Return the parameters identifying the target request, or an empty map.
  - startExpirationPeriod
```
public void startExpirationPeriod(int timeToLive)
```
    Start the expiration period for this instance.
    参数:
    timeToLive - the number of seconds before expiration
  - setExpirationTime
```
public void setExpirationTime(long expirationTime)
```
    Set the expiration time for the FlashMap. This is provided for serialization purposes but can also be used instead startExpirationPeriod(int).
    从以下版本开始:
    4.2
  - getExpirationTime
```
public long getExpirationTime()
```
    Return the expiration time for the FlashMap or -1 if the expiration period has not started.
    从以下版本开始:
    4.2
  - isExpired
```
public boolean isExpired()
```
    Return whether this instance has expired depending on the amount of elapsed time since the call to startExpirationPeriod(int).
  - compareTo
```
public int compareTo(FlashMap other)
```
    Compare two FlashMaps and prefer the one that specifies a target URL path or has more target URL parameters. Before comparing FlashMap instances ensure that they match a given request.
    指定者:
    compareTo 在接口中 Comparable<FlashMap>
  - equals
```
public boolean equals(@Nullable
                      Object other)
```
    指定者:
    equals 在接口中 Map<String,Object>
    覆盖:
    equals 在类中 AbstractMap<String,Object>
  - hashCode
```
public int hashCode()
```
    指定者:
    hashCode 在接口中 Map<String,Object>
    覆盖:
    hashCode 在类中 AbstractMap<String,Object>
  - toString
```
public String toString()
```
    覆盖:
    toString 在类中 AbstractMap<String,Object>

类 FlashMap

嵌套类概要

从类继承的嵌套类/接口 java.util.AbstractMap

从接口继承的嵌套类/接口 java.util.Map

构造器概要

方法概要

从类继承的方法 java.util.HashMap

从类继承的方法 java.lang.Object

构造器详细资料

FlashMap

方法详细资料

setTargetRequestPath

getTargetRequestPath

addTargetRequestParams

addTargetRequestParam

getTargetRequestParams

startExpirationPeriod

setExpirationTime

getExpirationTime

isExpired

compareTo

equals

hashCode

toString