java.lang.Object
- org.springframework.boot.loader.util.SystemPropertyUtils

```
public abstract class SystemPropertyUtils
extends Object
```
Helper class for resolving placeholders in texts. Usually applied to file paths.
A text may contain $ ... placeholders, to be resolved as system properties: e.g. $ user.dir . Default values can be supplied using the ":" separator between key and value.
Adapted from Spring.
另请参阅:
System.getProperty(String)

字段概要

字段
修饰符和类型	字段	说明
`static String`	`PLACEHOLDER_PREFIX`	Prefix for system property placeholders: "${".
`static String`	`PLACEHOLDER_SUFFIX`	Suffix for system property placeholders: "}".
`static String`	`VALUE_SEPARATOR`	Value separator for system property placeholders: ":".

构造器概要
构造器
构造器说明
SystemPropertyUtils()

方法概要

所有方法静态方法具体方法
修饰符和类型	方法	说明
`static String`	`getProperty(String key)`
`static String`	`getProperty(String key, String defaultValue)`
`static String`	`getProperty(String key, String defaultValue, String text)`	Search the System properties and environment variables for a value with the provided key.
`static String`	`resolvePlaceholders(String text)`	Resolve ${...} placeholders in the given text, replacing them with corresponding system property values.
`static String`	`resolvePlaceholders(Properties properties, String text)`	Resolve ${...} placeholders in the given text, replacing them with corresponding system property values.

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

- 字段详细资料
  - PLACEHOLDER_PREFIX
```
public static final String PLACEHOLDER_PREFIX
```
    Prefix for system property placeholders: "${".
    另请参阅:
    常量字段值
  - PLACEHOLDER_SUFFIX
```
public static final String PLACEHOLDER_SUFFIX
```
    Suffix for system property placeholders: "}".
    另请参阅:
    常量字段值
  - VALUE_SEPARATOR
```
public static final String VALUE_SEPARATOR
```
    Value separator for system property placeholders: ":".
    另请参阅:
    常量字段值
- 构造器详细资料
  - SystemPropertyUtils
```
public SystemPropertyUtils()
```
- 方法详细资料
  - resolvePlaceholders
```
public static String resolvePlaceholders(String text)
```
    Resolve ${...} placeholders in the given text, replacing them with corresponding system property values.
    参数:
    text - the String to resolve
    返回:
    the resolved String
    抛出:
    IllegalArgumentException - if there is an unresolvable placeholder
    另请参阅:
    PLACEHOLDER_PREFIX, PLACEHOLDER_SUFFIX
  - resolvePlaceholders
```
public static String resolvePlaceholders(Properties properties,
                                         String text)
```
    Resolve ${...} placeholders in the given text, replacing them with corresponding system property values.
    参数:
    properties - a properties instance to use in addition to System
    text - the String to resolve
    返回:
    the resolved String
    抛出:
    IllegalArgumentException - if there is an unresolvable placeholder
    另请参阅:
    PLACEHOLDER_PREFIX, PLACEHOLDER_SUFFIX
  - getProperty
```
public static String getProperty(String key)
```
  - getProperty
```
public static String getProperty(String key,
                                 String defaultValue)
```
  - getProperty
```
public static String getProperty(String key,
                                 String defaultValue,
                                 String text)
```
    Search the System properties and environment variables for a value with the provided key. Environment variables in UPPER_CASE style are allowed where System properties would normally be lower.case.
    参数:
    key - the key to resolve
    defaultValue - the default value
    text - optional extra context for an error message if the key resolution fails (e.g. if System properties are not accessible)
    返回:
    a static property value or null of not found

类 SystemPropertyUtils

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

PLACEHOLDER_PREFIX

PLACEHOLDER_SUFFIX

VALUE_SEPARATOR

构造器详细资料

SystemPropertyUtils

方法详细资料

resolvePlaceholders

resolvePlaceholders

getProperty

getProperty

getProperty