操作properties文件

发个例子大家自己看哈.
package control;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.Properties;

public class TestMain {
?
?//根据key读取value
?public static String readValue(String filePath,String key) {
??Properties props = new Properties();
??????? try {
??????? ?InputStream in = new BufferedInputStream (new FileInputStream(filePath));
??????? ?props.load(in);
??????? ?String value = props.getProperty (key);
??????????? System.out.println(key+value);
??????????? return value;
??????? } catch (Exception e) {
??????? ?e.printStackTrace();
??????? ?return null;
??????? }
?}
?
?//读取properties的全部信息
??? public static void readProperties(String filePath) {
??? ?Properties props = new Properties();
??????? try {
??????? ?InputStream in = new BufferedInputStream (new FileInputStream(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();
??????? }
??? }

??? //写入properties信息
??? public static void writeProperties(String filePath,String parameterName,String parameterValue) {
??? ?Properties prop = new Properties();
??? ?try {
??? ??InputStream fis = new FileInputStream(filePath);
??????????? //从输入流中读取属性列表（键和元素对）
??????????? prop.load(fis);
??????????? //调用 Hashtable 的方法 put。使用 getProperty 方法提供并行性。
??????????? //强制要求为属性的键和值使用字符串。返回值是 Hashtable 调用 put 的结果。
??????????? OutputStream fos = new FileOutputStream(filePath);
??????????? prop.setProperty(parameterName, parameterValue);
??????????? //以适合使用 load 方法加载到 Properties 表中的格式，
??????????? //将此 Properties 表中的属性列表（键和元素对）写入输出流
??????????? prop.store(fos, "Update '" + parameterName + "' value");
??????? } catch (IOException e) {
??????? ?System.err.println("Visit "+filePath+" for updating "+parameterName+" value error");
??????? }
??? }

??? public static void main(String[] args) {
??? ?readValue("info.properties","url");
??????? writeProperties("info.properties","age","21");
??????? readProperties("info.properties" );
??????? System.out.println("OK");
??? }
}

引用http://www.blogjava.net/action/archive/2006/08/21/64804.html