web 工程下 java操作属性文件保存在classes下的读写操作

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.Enumeration;

import java.util.Properties;

import org.apache.commons.lang.StringUtils;

public class PropertiesUtil {

// 根据key读取value

public static String readValue(String filePath, String key) {

InputStream in = null;

String value = null;

try {

Properties props = new Properties();

if (StringUtils.isBlank(filePath))

filePath = "/constants.properties";

in = (new PropertiesUtil()).getClass()

.getResourceAsStream(filePath);

props.load(in);

if(props.containsKey(key)){

value = props.getProperty(key);

}

} catch (Exception e) {

} finally {

try {

if (in != null) {

in.close();

in = null;

}

} catch (Exception e) {

}

}

return value;

}

// 读取properties的全部信息

@SuppressWarnings("unchecked")

public static void readProperties(String filePath) {

InputStream in = null;

try {

Properties props = new Properties();

if (StringUtils.isBlank(filePath))

filePath = "/constants.properties";

in = (new PropertiesUtil()).getClass()

.getResourceAsStream(filePath);

props.load(in);

Enumeration en = props.propertyNames();

while (en.hasMoreElements()) {

String key = (String) en.nextElement();

String Property = props.getProperty(key);

System.out.println(key + Property);

}

} catch (Exception e) {

// e.printStackTrace();

// System.err.println("ConfigInfoError" + e.toString());

}

}

// 写入properties信息

public static void writeProperties(String filePath, String parameterName,

String parameterValue) {

OutputStream fos = null;

try {

Properties prop = new Properties();

if (StringUtils.isBlank(filePath))

filePath = "constants.properties";

fos = new FileOutputStream((new PropertiesUtil()).getClass().getResource("/").getPath()+filePath);

prop.setProperty(parameterName, parameterValue);

prop.store(fos, "Update '" + parameterName + "' value");

} catch (IOException e) {

// e.printStackTrace();

}finally {

try {

if(fos != null) {

fos.close();

fos = null;

}

} catch (Exception e) {

}

}

}

public static void main(String args[]) {

String filePath = "constants.properties";

PropertiesUtil.writeProperties(filePath, "qq1112", "ww222111nnnmmmm");

System.out.println(PropertiesUtil.readValue("/"+filePath, "qq1112"));

}

}