JAVA学习提高之－－－－JAVA读写Properties文件

package com.lwf.util;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.Properties;

/*
* 从路径中的属性文件中读取单个属性或全部属性及设置属性
*/
public class GetProperty {
public static String readValue(String filePath,String key){
Properties props = new Properties();
try {
InputStream ips = new BufferedInputStream(new FileInputStream(filePath));
props.load(ips);
String value = props.getProperty(key);
System.out.println(key+"="+value);
return value;
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}

}

//读取全部信息
public static void readProperties(String filePath) {
Properties props = new Properties();
try {
InputStream ips = new BufferedInputStream(new FileInputStream(filePath));
props.load(ips);
Enumeration enum = props.propertyNames();
while(enum.hasMoreElements()){
String key = (String)enum.nextElement();
String value = props.getProperty(key);
System.out.println(key+"="+value);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}

public static void writeProperties(String filePath,String paraKey,String paraValue){
Properties props = new Properties();
try {

OutputStream ops = new FileOutputStream(filePath);
props.setProperty(paraKey, paraValue);
props.store(ops, "set");
} catch (IOException e) {
e.printStackTrace();
}
}

public static void main(String[] args){
GetProperty.readValue("D:\\eclipse3.3\\workspace\\Test\\src\\sys.properties", "username");

GetProperty.readProperties("D:\\eclipse3.3\\workspace\\Test\\src\\sys.properties");
GetProperty.writeProperties("D:\\eclipse3.3\\workspace\\Test\\src\\sys.properties", "age", "21");
}
}