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【第13章：Java类集】_属性类：Properties

发布时间：2021-01-04 15:12:45编辑：雪饮阅读（）

 Properties类用于属性的读写等操作

属性的设置与获取
import java.util.Properties;
public class Hello{
   public static void main(String args[]){
              Properties pro=new Properties();
              pro.setProperty("kasumi","霞");
              pro.setProperty("ayane","凌音");
              pro.setProperty("momiji","红叶");
              System.out.println(pro.getProperty("momiji"));
   }
};

getProperty方法获取属性时第二个参数可以设置默认值
即当获取对应属性不存在时候则返回提供的这个默认值
import java.util.Properties;
public class Hello{
   public static void main(String args[]){
              Properties pro=new Properties();
              System.out.println(pro.getProperty("momiji","红叶"));
   }
};
D:\>javac Hello.java
D:\>java Hello
红叶
store方法可以将属性信息保存到文件中
import java.util.Properties;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
public class Hello{
   public static void main(String args[]){
              Properties pro=new Properties();
              pro.setProperty("kasumi","霞");
              pro.setProperty("ayane","凌音");
              pro.setProperty("momiji","红叶");
              File file=new File("D:"+File.separator+"momiji.properties");
              try{
                     pro.store(new FileOutputStream(file),"person info");
              }
              catch(FileNotFoundException e){
                     e.printStackTrace();
              }
              catch(IOException e){
                     e.printStackTrace();
              }
   }
};
D:\>javac Hello.java
D:\>java Hello
load方法可以从文件中读取属性信息
import java.util.Properties;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.FileInputStream;
public class Hello{
   public static void main(String args[]){
              Properties pro=new Properties();
              File file=new File("D:"+File.separator+"momiji.properties");
              try{
                     pro.load(new FileInputStream(file));
                     System.out.println(pro.getProperty("kasumi"));
              }
              catch(FileNotFoundException e){
                     e.printStackTrace();
              }
              catch(IOException e){
                     e.printStackTrace();
              }
   }
};
D:\>javac Hello.java
D:\>java Hello
霞
storeToXML方法可以将属性信息保存到xml文件中
import java.util.Properties;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.FileInputStream;
public class Hello{
   public static void main(String args[]){
              Properties pro=new Properties();
              pro.setProperty("kasumi","霞");
              pro.setProperty("ayane","凌音");
              pro.setProperty("momiji","红叶");
              File file=new File("D:"+File.separator+"momiji.xml");
              try{
                     pro.storeToXML(new FileOutputStream(file),"momiji xml info");
              }
              catch(FileNotFoundException e){
                     e.printStackTrace();
              }
              catch(IOException e){
                     e.printStackTrace();
              }
   }
};
D:\>javac Hello.java
D:\>java Hello
loadFromXML方法用于从xml文件中读取属性信息
import java.util.Properties;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.FileInputStream;
public class Hello{
   public static void main(String args[]){
              Properties pro=new Properties();
              File file=new File("D:"+File.separator+"momiji.xml");
              try{
                     pro.loadFromXML(new FileInputStream(file));
                     System.out.println(pro.getProperty("momiji"));
              }
              catch(FileNotFoundException e){
                     e.printStackTrace();
              }
              catch(IOException e){
                     e.printStackTrace();
              }
   }
};
D:\>javac Hello.java
D:\>java Hello
红叶