Java中对Properties的操作

Java中对Properties的操作

如果，项目中对properties文件的CURD操作比较多，建议建个工具类，方便调用。如下：

package com.properties;

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

public class OperatePropertiesUtil{
	//加载、读取Properties文件
	public static Properties loadProperties(String propertiesPath){
		Properties pps = new Properties();
		try {
			InputStream in = new FileInputStream(propertiesPath);
			pps.load(in);
			in.close();
		}catch (IOException e) {
			e.printStackTrace();
		}
		return pps;
	}
	//向Properties文件中加入数据
	public static Properties addProperties(String propertiesPath,Properties pps,String key,String value){
		try {
			OutputStream fos = new FileOutputStream(propertiesPath);
			pps.setProperty(key, value);
			pps.store(fos, "Update '" + key + "' value");
			fos.close();
		}catch (IOException e) {
			e.printStackTrace();
		}
		return pps;
	}
	//从Properties文件中根据key删除
	public static Properties removeProperties(String propertiesPath,Properties pps,String key){
		try {
			OutputStream oFile = new FileOutputStream(propertiesPath);
			pps.remove(key);
			pps.store(oFile, "Delete '" + key);
			oFile.close();
		}catch (IOException e) {
			e.printStackTrace();
		}
		return pps;
	}
	//Properties文件中根据key更新value
	public static Properties updatePropertiesByKey(String propertiesPath,Properties pps,String key,String value){
		try {
			OutputStream oFile = new FileOutputStream(propertiesPath);
			pps.setProperty(key, value);
			pps.store(oFile, "Update '" + key);
			oFile.close();
		}catch (IOException e) {
			e.printStackTrace();
		}
		return pps;
	}
	//update Properties文件,以byte[]的形式，重新向properties中写入，特殊情况用
	public static Properties updateProperties(String propertiesPath,Properties pps,byte [] str){
		try {
			File file = new File(propertiesPath);
			FileOutputStream oFile = new FileOutputStream(file);
			oFile.write(str);
			oFile.close();
		}catch (IOException e) {
			e.printStackTrace();
		}
		return pps;
	}
}

如果是javaweb项目，文件的路径只能取到已经部署到的服务下的webapp下的文件路径。

比如这样：String path = request.getServletContext().getRealPath("/");

 String realPath = path+"WEB-INF\\classes"+"文件名.后缀名";

或者其他的取路径方法也可。

下面是调用方法，这些可以自己在项目中根据情况具体封装。

package com.properties;

import java.util.Properties;
import java.util.Set;

public class TestCurd {

	public static void main(String[] args) {
		String propertiesPath = "你的文件路径";
		Properties pps = OperatePropertiesUtil.loadProperties(propertiesPath);
		//showPro(pps);
		//showPro(addPro(propertiesPath, pps));
		//showPro(removePro(propertiesPath, pps));
		//showPro(updateProByKey(propertiesPath, pps));
		//showPro(updatePro(propertiesPath, pps));
	}
	//遍历显示properties
	public static void showPro(Properties pps){
		Set<Object> set = pps.keySet();
		for (Object object : set) {
			System.out.println("key:"+(String)object+"\t"+"value:"+pps.getProperty((String)object));
		}
	}
	//向properties添加数据
	public static Properties addPro(String propertiesPath,Properties pps){
		Properties ppss = OperatePropertiesUtil.addProperties(propertiesPath, pps,"addkey","addvalue"); 
		return ppss;
	}
	//向properties删除数据
	public static Properties removePro(String propertiesPath,Properties pps){
		Properties ppss = OperatePropertiesUtil.removeProperties(propertiesPath, pps,"addkey"); 
		return ppss;
	}
	//更新properties数据
	public static Properties updateProByKey(String propertiesPath,Properties pps){
		Properties ppss = OperatePropertiesUtil.updatePropertiesByKey(propertiesPath, pps,"addkey","updateValue"); 
		return ppss;
	}
	//以byte[]的形式重新写入properties数据
	//javaweb项目中，只能操作webapp下的properties文件，每次操作并不会覆盖原始版本，此时可用此方法。
	public static Properties updatePro(String propertiesPath,Properties pps){
		Set<Object> sett = pps.keySet();
		StringBuffer strbu = new StringBuffer("");
		for (Object object : sett) {
			if("addkey".equals((String)object)){
				strbu = strbu.append((String)object+"="+"uValue2"+"\n");
			}else{
				String res = pps.getProperty((String)object);
				strbu = strbu.append((String)object+"="+res+"\n");
			}
		}
		byte [] str = strbu.toString().getBytes();
		Properties ppss = OperatePropertiesUtil.updateProperties(propertiesPath,pps,str); 
		return ppss;
	}
}