配置文件PropertiesUtil

配置文件 system.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc\:mysql\://localhost\:3306/yzuzhang
jdbc.username=root
jdbc.password=123456

具体实现代码：

package com.javaweb.utils;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import org.apache.commons.io.IOUtils;

public class PropertiesUtil {

    /**
     * @param key
     * @return
     * @throws IOException
     */
    public static String readProperties(String key){
        String value = null;
        InputStream inputStream = null;
        try {
            Properties p = new Properties();
            String path = Thread.currentThread().getContextClassLoader()
                    .getResource("config/system.properties").getPath();
            //路径也可以这样获取
            path = PropertiesUtil.class.getClassLoader().getResource("config/system.properties").getPath();
            System.out.println(path);
            
            inputStream = new FileInputStream(path);
            if (null != inputStream) {
                p.load(inputStream);
                value = p.getProperty(key);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            IOUtils.closeQuietly(inputStream);
        }
        
        return value;
    }
    
    /**
     * @param key
     * @return
     * @throws IOException
     */
    public static String getProperty(String key){
        String value = null;
        InputStream inputStream = null;
        try {
            Properties p = new Properties();
            inputStream = PropertiesUtil.class.getClassLoader().
                getResourceAsStream("config/system.properties");
            if (null != inputStream) {
                p.load(inputStream);
                value = p.getProperty(key);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            IOUtils.closeQuietly(inputStream);
        }
        
        return value;
    }
    
    public static void main(String[] args) throws IOException {
        System.out.println("jdbc.username === "+getProperty("jdbc.username"));
        System.out.println("jdbc.driver === "+readProperties("jdbc.driver"));
    }
}

控制台输出的结果如下：

jdbc.username === root
/E:/Workspaces/yzuzhang/WebRoot/WEB-INF/classes/config/system.properties
jdbc.driver === com.mysql.jdbc.Driver