[J2SE] J2SE API读取Properties文件的六种方法

使用J2SE API读取Properties文件的六种方法：
1.使用java.util.Properties类的load()方法
示例： InputStream in = lnew BufferedInputStream(new FileInputStream(name));
Properties p = new Properties();
p.load(in);
2.使用java.util.ResourceBundle类的getBundle()方法
示例： ResourceBundle rb = ResourceBundle.getBundle(name, Locale.getDefault());
3.使用java.util.PropertyResourceBundle类的构造函数
示例： InputStream in = new BufferedInputStream(new FileInputStream(name));
ResourceBundle rb = new PropertyResourceBundle(in);
4.使用class变量的getResourceAsStream()方法
示例： InputStream in = JProperties.class.getResourceAsStream(name);
Properties p = new Properties();
p.load(in);
5.使用class.getClassLoader()所得到的java.lang.ClassLoader的getResourceAsStream()方法
示例： InputStream in = JProperties.class.getClassLoader().getResourceAsStream(name);
Properties p = new Properties();
p.load(in);
6.使用java.lang.ClassLoader类的getSystemResourceAsStream()静态方法

示例： InputStream in = ClassLoader.getSystemResourceAsStream(name);
Properties p = new Properties();
p.load(in);
补充
Servlet中可以使用javax.servlet.ServletContext的getResourceAsStream()方法
示例：InputStream in = context.getResourceAsStream(path);
Properties p = new Properties();
p.load(in);
完整的示例:
JProperties.java文件
package com.kindani;

//import javax.servlet.ServletContext;
import java.util.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.io.FileInputStream;

/**
* 使用J2SE API?取Properties文件的六种方法
* User: SYNFORM
* Date: 2005/07/12
* Time: 18:40:55
* To change this template use File | Settings | File Templates.
*/
public class JProperties {

  public final static int BY_PROPERTIES = 1;
  public final static int BY_RESOURCEBUNDLE = 2;
  public final static int BY_PROPERTYRESOURCEBUNDLE = 3;
  public final static int BY_CLASS = 4;
  public final static int BY_CLASSLOADER = 5;
  public final static int BY_SYSTEM_CLASSLOADER = 6;

  public final static Properties loadProperties(
final String name, final int type) throws IOException {
    Properties p = new Properties();
    InputStream in = null;
    if (type == BY_PROPERTIES) {
      in = new BufferedInputStream(new FileInputStream(name));
      assert (in != null);
      p.load(in);
    } else if (type == BY_RESOURCEBUNDLE) {
      ResourceBundle rb = ResourceBundle.getBundle(name, Locale.getDefault());
      assert (rb != null);
      p = new ResourceBundleAdapter(rb);
    } else if (type == BY_PROPERTYRESOURCEBUNDLE) {
      in = new BufferedInputStream(new FileInputStream(name));
      assert (in != null);
      ResourceBundle rb = new PropertyResourceBundle(in);
      p = new ResourceBundleAdapter(rb);
    } else if (type == BY_CLASS) {
      assert (JProperties.class.equals(new JProperties().getClass()));
      in = JProperties.class.getResourceAsStream(name);
      assert (in != null);
      p.load(in);
      //return new JProperties().getClass().getResourceAsStream(name);
    } else if (type == BY_CLASSLOADER) {
      assert (JProperties.class.getClassLoader().equals(
new JProperties().getClass().getClassLoader()));
      in = JProperties.class.getClassLoader().getResourceAsStream(name);
      assert (in != null);
      p.load(in);
      //return new JProperties().getClass().
getClassLoader().getResourceAsStream(name);
    } else if (type == BY_SYSTEM_CLASSLOADER) {
      in = ClassLoader.getSystemResourceAsStream(name);
      assert (in != null);
      p.load(in);
    }

    if (in != null) {
      in.close();
    }
    return p;

  }

  // ---------------------------------------------- servlet used
/*
  public static Properties loadProperties(
ServletContext context, String path) throws IOException {
    assert (context != null);
    InputStream in = context.getResourceAsStream(path);
    assert (in != null);
    Properties p = new Properties();
    p.load(in);
    in.close();
    return p;
  }
*/

  // ---------------------------------------------- support class

  /**
   * ResourceBundle Adapter class.
   */
  public static class ResourceBundleAdapter extends Properties {
    public ResourceBundleAdapter(ResourceBundle rb) {
      assert (rb instanceof java.util.PropertyResourceBundle);
      this.rb = rb;
      java.util.Enumeration e = rb.getKeys();
      while (e.hasMoreElements()) {
        Object o = e.nextElement();
        this.put(o, rb.getObject((String) o));
      }
    }

    private ResourceBundle rb = null;

    public ResourceBundle getBundle(String baseName) {
      return ResourceBundle.getBundle(baseName);
    }

    public ResourceBundle getBundle(String baseName, Locale locale) {
      return ResourceBundle.getBundle(baseName, locale);
    }

    public ResourceBundle getBundle(String baseName,
Locale locale, ClassLoader loader) {
      return ResourceBundle.getBundle(baseName, locale, loader);
    }

    public Enumeration<String> getKeys() {
      return rb.getKeys();
    }

    public Locale getLocale() {
      return rb.getLocale();
    }

    public Object getObject(String key) {
      return rb.getObject(key);
    }

    public String getString(String key) {
      return rb.getString(key);
    }

    public String[] getStringArray(String key) {
      return rb.getStringArray(key);
    }

    protected Object handleGetObject(String key) {
      return ((PropertyResourceBundle) rb).handleGetObject(key);
    }

  }

}
JPropertiesTest.java文件
package com.kindani.test;

import junit.framework.*;
import com.kindani.JProperties;

//import javax.servlet.ServletContext;
import java.util.Properties;

public class JPropertiesTest extends TestCase {
  JProperties jProperties;
  String key = "helloworld.title";
  String value = "Hello World!";

  public void testLoadProperties() throws Exception {
    String name = null;
    Properties p = new Properties();

    name = "C:\\IDEAP\\Properties4Methods\\src\\com\\
kindani\\test\\LocalStrings.properties";
    p = JProperties.loadProperties(name, JProperties.BY_PROPERTIES);
    assertEquals(value, p.getProperty(key));

    name = "com.kindani.test.LocalStrings";
    p = JProperties.loadProperties(name,JProperties.BY_RESOURCEBUNDLE);
    assertEquals(value, p.getProperty(key));
    assertEquals(value,((JProperties.ResourceBundleAdapter)p).getString(key));

    name = "C:\\IDEAP\\Properties4Methods\\src\\com\\
kindani\\test\\LocalStrings.properties";
    p = JProperties.loadProperties(name, JProperties.BY_PROPERTYRESOURCEBUNDLE);
    assertEquals(value, p.getProperty(key));
    assertEquals(value,((JProperties.ResourceBundleAdapter)p).getString(key));

    name = "\\com\\kindani\\test\\LocalStrings.properties";
    p = JProperties.loadProperties(name, JProperties.BY_SYSTEM_CLASSLOADER);
    assertEquals(value, p.getProperty(key));

    name = "\\com\\kindani\\test\\LocalStrings.properties";
    p = JProperties.loadProperties(name, JProperties.BY_CLASSLOADER);
    assertEquals(value, p.getProperty(key));

    name = "test\\LocalStrings.properties";
    p = JProperties.loadProperties(name, JProperties.BY_CLASS);
    assertEquals(value, p.getProperty(key));
  }

/*
  public void testLoadProperties2() throws Exception {
    ServletContext context = null;
    String path = null;
    Properties p = null;
    path = "/WEB-INF/classes/LocalStrings.properties";
    p = JProperties.loadProperties(context, path);
    assertEquals(value, p.getProperty(key));
  }
*/
}
properties文件与JPropertiesTest.java文件相同的目录下
LocalStrings.properties文件
# $Id: LocalStrings.properties,v 1.1 2000/08/17 00:57:52 horwat Exp $

# Default localized resources for example servlets
# This locale is en_US

helloworld.title=Hello World!

requestinfo.title=Request Information Example
requestinfo.label.method=Method:
requestinfo.label.requesturi=Request URI:
requestinfo.label.protocol=Protocol:
requestinfo.label.pathinfo=Path Info:
requestinfo.label.remoteaddr=Remote Address:

requestheader.title=Request Header Example

requestparams.title=Request Parameters Example
requestparams.params-in-req=Parameters in this request:
requestparams.no-params=No Parameters, Please enter some
requestparams.firstname=First Name:
requestparams.lastname=Last Name:

cookies.title=Cookies Example
cookies.cookies=Your browser is sending the following cookies:
cookies.no-cookies=Your browser isn&#39;t sending any cookies
cookies.make-cookie=Create a cookie to send to your browser
cookies.name=Name:
cookies.value=Value:
cookies.set=You just sent the following cookie to your browser:

sessions.title=Sessions Example
sessions.id=Session ID:
sessions.created=Created:
sessions.lastaccessed=Last Accessed:
sessions.data=The following data is in your session:
sessions.adddata=Add data to your session
sessions.dataname=Name of Session Attribute:
sessions.datavalue=Value of Session Attribute: