有时候不要把一些属性值写死在代码中，而是写在配置在文件中，方便更改

 

PropertiesUtil工具类：读取key-value形式的配置文件，根据key获得value值 

 

1、测试类

 

public class Test{	private static PropertiesUtil propertiesUtil = new PropertiesUtil("file.properties");	//根据文件中的key获取value值	String value = propertiesUtil.getStringProperty("文件中的key");	}

　　

 

 2、PropertiesUtil.java工具类

package com.util;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStreamReader;import java.util.Collection;import java.util.Properties;import java.util.Set;import org.apache.log4j.Logger;public class PropertiesUtil {		private static final Logger LOGGER = Logger.getLogger(PropertiesUtil.class);	private final Properties props;	public PropertiesUtil(final Properties props) {		this.props = props;	}	public PropertiesUtil(final String propertiesFileName) {		final Properties properties = new Properties();		InputStreamReader in = null;		try {			in = new InputStreamReader(new FileInputStream(this.getClass().getResource("/").getPath()+propertiesFileName), "UTF-8");			/*			 * 获取当前工程根目录			 * in = new InputStreamReader(new FileInputStream(System.getProperty("user.dir") + File.separator + propertiesFileName), "UTF-8");			 */			properties.load(in);		} catch (final IOException ioe) {			LOGGER.error("Unable to read " + propertiesFileName, ioe);		} finally {			if (in != null) {				try {					in.close();				} catch (final IOException ioe) {					LOGGER.error("Unable to close " + propertiesFileName, ioe);				}			}		}		this.props = properties;	}	public String getStringProperty(final String name) {		return props.getProperty(name);	}	public int getIntegerProperty(final String name, final int defaultValue) {		String prop = props.getProperty(name);		if (prop != null) {			try {				return Integer.parseInt(prop);			} catch (final Exception ignored) {				return defaultValue;			}		}		return defaultValue;	}	public long getLongProperty(final String name, final long defaultValue) {		String prop = props.getProperty(name);		if (prop != null) {			try {				return Long.parseLong(prop);			} catch (final Exception ignored) {				return defaultValue;			}		}		return defaultValue;	}	public float getFloatProperty(final String name,final float defaultValue)	{		String prop = props.getProperty(name);		if (prop != null) {			try {				return Float.parseFloat(prop);			} catch (final Exception ignored) {				return defaultValue;			}		}		return defaultValue;	}		public String getStringProperty(final String name, final String defaultValue) {		final String prop = getStringProperty(name);		return (prop == null) ? defaultValue : prop;	}	public boolean getBooleanProperty(final String name) {		return getBooleanProperty(name, false);	}	public boolean getBooleanProperty(final String name, final boolean defaultValue) {		final String prop = getStringProperty(name);		return (prop == null) ? defaultValue : "true".equalsIgnoreCase(prop);	}		public Set