import java.io.IOException;
import java.io.InputStream;
import java.util.NoSuchElementException;
import java.util.Properties;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
/**
* Properties文件载入工具类. 可载入多个properties文件, *相同的属性在最后载入的文件中的值将会覆盖之前的值,但以System的Property优先.
*/
public class PropertiesLoader {
private static Logger logger = LoggerFactory.getLogger(PropertiesLoader.class);
private static ResourceLoader resourceLoader = new DefaultResourceLoader();
private final Properties properties;
public PropertiesLoader(String... resourcesPaths) {
properties = loadProperties(resourcesPaths);
}
public Properties getProperties() {
return properties;
}
/**
* 取出Property,但以System的Property优先,取不到返回空字符串.
*/
private String getValue(String key) {
String systemProperty = System.getProperty(key);
if (systemProperty != null) {
return systemProperty;
}
if (properties.containsKey(key)) {
return properties.getProperty(key);
}
return "";
}
/**
* 取出String类型的Property,但以System的Property优先,如果都为Null则抛出异常.
*/
public String getProperty(String key) {
String value = getValue(key);
if (value == null) {
throw new NoSuchElementException();
}
return value;
}
/**
* 取出String类型的Property,但以System的Property优先.如果都为Null则返回Default值.
*/
public String getProperty(String key, String defaultValue) {
String value = getValue(key);
return value != null ? value : defaultValue;
}
/**
* 取出Integer类型的Property,但以System的Property优先.如果都为Null或内容错误则抛出异常.
*/
public Integer getInteger(String key) {
String value = getValue(key);
if (value == null) {
throw new NoSuchElementException();
}
return Integer.valueOf(value);
}
/**
* 取出Integer类型的Property,但以System的Property优先.如果都为Null则返回Default值,如果内容错误则抛出异常
*/
public Integer getInteger(String key, Integer defaultValue) {
String value = getValue(key);
return value != null ? Integer.valueOf(value) : defaultValue;
}
/**
* 取出Double类型的Property,但以System的Property优先.如果都为Null或内容错误则抛出异常.
*/
public Double getDouble(String key) {
String value = getValue(key);
if (value == null) {
throw new NoSuchElementException();
}
return Double.valueOf(value);
}
/**
* 取出Double类型的Property,但以System的Property优先.如果都为Null则返回Default值,如果内容错误则抛出异常
*/
public Double getDouble(String key, Integer defaultValue) {
String value = getValue(key);
return value != null ? Double.valueOf(value) : defaultValue;
}
/**
* 取出Boolean类型的Property,但以System的Property优先.如果都为Null抛出异常,如果内容不是true/false则返回false.
*/
public Boolean getBoolean(String key) {
String value = getValue(key);
if (value == null) {
throw new NoSuchElementException();
}
return Boolean.valueOf(value);
}
/**
* 取出Boolean类型的Property,但以System的Property优先.如果都为Null则返回Default值,如果内容不为true/false则返回false.
*/
public Boolean getBoolean(String key, boolean defaultValue) {
String value = getValue(key);
return value != null ? Boolean.valueOf(value) : defaultValue;
}
/**
* 载入多个文件, 文件路径使用Spring Resource格式.
*/
private Properties loadProperties(String... resourcesPaths) {
Properties props = new Properties();
for (String location : resourcesPaths) {
logger.debug("Loading properties file from:" + location);
InputStream is = null;
try {
Resource resource = resourceLoader.getResource(location);
is = resource.getInputStream();
props.load(is);
} catch (IOException ex) {
logger.info("Could not load properties from path:" + location + ", " + ex.getMessage());
} finally {
IOUtils.closeQuietly(is);
}
}
return props;
}
}