properties种学习

properties类学习
 

 

package configuration;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

public class Configuration {
 private Properties properties;
 private FileInputStream inputFile;
 private FileOutputStream outputFile;
 
 public Configuration(){
  properties = new Properties();
 }
 public Configuration(String filePath){
  properties = new Properties();
  try{
//   inputFile = (FileInputStream) Configuration.class.getClassLoader().get(filePath);
   inputFile = new FileInputStream(filePath);
   properties.load(inputFile);
   inputFile.close();
  }catch(FileNotFoundException ex){
   System.out.println("读取属性文件错误");
   ex.printStackTrace();
  }catch(IOException ex){
   System.out.println("载入文件错误");
   ex.printStackTrace();
  }
 }
 
 public String getValue(String key){
  if(properties.containsKey(key)){
   String value = properties.getProperty(key);
   return value;
  }
  else
   return "";
 }
 public String getValue(String fileName,String key){
  String value = "";
  try{
   inputFile = new FileInputStream(fileName);
   properties.load(inputFile);
   inputFile.close();
   if(properties.containsKey(key)){
    value = properties.getProperty(key);
    return value;
   }else{
    return value;
   }
  }catch(FileNotFoundException ex){
   System.out.println("读取属性文件错误");
   ex.printStackTrace();
  }catch(IOException ex){
   System.out.println("载入文件错误");
   ex.printStackTrace();
  }
  return value;
 }
 public void clear(){
  properties.clear();
 }
 
 public void setValue(String key,String value){
  properties.setProperty(key, value);
 }
 public void saveFile(String fileName,String description){
  try{
   outputFile = new FileOutputStream(fileName);
   properties.store(outputFile, description);
   outputFile.close();
  }catch(FileNotFoundException ex){
   System.out.println("读取属性文件错误");
   ex.printStackTrace();
  }catch(IOException ex){
   System.out.println("载入文件错误");
   ex.printStackTrace();
  }
 }
 public static void main(String[] args){
  Configuration rc = new Configuration("test.properties");
  String ip = rc.getValue("ip");
  String host = rc.getValue("dbPort");
  String tab = rc.getValue("dbTable");
  System.out.println("ip = " + ip + "ip-test leng = " + "ip-test".length());//以下输出properties读出的值
        System.out.println("ip's length = " + ip.length());
        System.out.println("host = " + host);
        System.out.println("tab = " + tab);

 }
}