Java常用类 - Properties读写配置文件

Java中读写资源文件最重要的类是Properties,功能大致如下：

1. 读写Properties文件

2. 读写XML文件

3. 不仅可以读写上述两类文件，还可以读写其它格式文件如txt等，只要符合key=value格式即可.

 

注意：资源文件中含有中文时的处理方法 

1. 将中文字符通过工作转成utf8编码，可以通过Java自带的nativetoascii或Eclipse中的属性编辑器。

2. 直接调用 new String(youChineseString.getBytes("ISO-8859-1"), "GBK");

 

附：WEB程序中加载资源文件的方法

Properties prop = null; 

1. prop = Thread.currentThread().getContextClassLoader().getResourceAsStream("filename");

2. prop = this.getClass().getClassLoader().getResourceAsStream("filename");

 

Properties能读取以key,value存储的任何格式文件，究竟有什么神奇，猫一眼类结构，

原来它继承了Hashtable并实现了Map接口,这样大家放心了吧。

在D:\的测试文件：

1、readfile.properties

username=myname
password=mypassword
chinese=中文
2、readxmlfile.xml  (注意保存为UTF-8格式)

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
<properties>
<entry key="password">mypassword</entry>
<entry key="chinese">中文</entry>
<entry key="username">myname</entry>
</properties>

测试代码：

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.io.UnsupportedEncodingException;  
import java.util.Properties;  
  
public class PropertiesTest  
{  
  
    public static void main(String[] args)  
    {  
  
        String readfile = "d:" + File.separator + "readfile.properties";  
        String writefile = "d:" + File.separator + "writefile.properties";  
        String readxmlfile = "d:" + File.separator + "readxmlfile.xml";  
        String writexmlfile = "d:" + File.separator + "writexmlfile.xml";  
        String readtxtfile = "d:" + File.separator + "readtxtfile.txt";  
        String writetxtfile = "d:" + File.separator + "writetxtfile.txt";  
  
        readPropertiesFile(readfile); //读取properties文件  
        writePropertiesFile(writefile); //写properties文件  
        readPropertiesFileFromXML(readxmlfile); //读取XML文件  
        writePropertiesFileToXML(writexmlfile); //写XML文件  
        readPropertiesFile(readtxtfile); //读取txt文件  
        writePropertiesFile(writetxtfile); //写txt文件  
    }  
  
    //读取资源文件,并处理中文乱码  
    public static void readPropertiesFile(String filename)  
    {  
        Properties properties = new Properties();  
        try  
        {  
            InputStream inputStream = new FileInputStream(filename);  
            properties.load(inputStream);  
            inputStream.close(); //关闭流  
        }  
        catch (IOException e)  
        {  
            e.printStackTrace();  
        }  
        String username = properties.getProperty("username");  
        String passsword = properties.getProperty("password");  
        String chinese = properties.getProperty("chinese");  
        try  
        {  
            chinese = new String(chinese.getBytes("ISO-8859-1"), "GBK"); // 处理中文乱码  
        }  
        catch (UnsupportedEncodingException e)  
        {  
            e.printStackTrace();  
        }  
        System.out.println(username);  
        System.out.println(passsword);  
        System.out.println(chinese);  
    }  
  
    //读取XML文件,并处理中文乱码  
    public static void readPropertiesFileFromXML(String filename)  
    {  
        Properties properties = new Properties();  
        try  
        {  
            InputStream inputStream = new FileInputStream(filename);  
            properties.loadFromXML(inputStream);  
            inputStream.close();  
        }  
        catch (IOException e)  
        {  
            e.printStackTrace();  
        }  
        String username = properties.getProperty("username");  
        String passsword = properties.getProperty("password");  
        String chinese = properties.getProperty("chinese"); //XML中的中文不用处理乱码，正常显示  
        System.out.println(username);  
        System.out.println(passsword);  
        System.out.println(chinese);  
    }  
  
    //写资源文件，含中文  
    public static void writePropertiesFile(String filename)  
    {  
        Properties properties = new Properties();  
        try  
        {  
            OutputStream outputStream = new FileOutputStream(filename);  
            properties.setProperty("username", "myname");  
            properties.setProperty("password", "mypassword");  
            properties.setProperty("chinese", "中文");  
            properties.store(outputStream, "author: shixing_11@sina.com");  
            outputStream.close();  
        }  
        catch (IOException e)  
        {  
            e.printStackTrace();  
        }  
    }  
  
    //写资源文件到XML文件，含中文    
    public static void writePropertiesFileToXML(String filename)  
    {  
        Properties properties = new Properties();  
        try  
        {  
            OutputStream outputStream = new FileOutputStream(filename);  
            properties.setProperty("username", "myname");  
            properties.setProperty("password", "mypassword");  
            properties.setProperty("chinese", "中文");  
            properties.storeToXML(outputStream, "author: shixing_11@sina.com");  
            outputStream.close();  
        }  
        catch (IOException e)  
        {  
            e.printStackTrace();  
        }  
    }  
  
}