Operate the properties file in Java

Package control;

Import java. Io. bufferedinputstream;
Import java. Io. fileinputstream;
Import java. Io. fileoutputstream;
Import java. Io. ioexception;
Import java. Io. inputstream;
Import java. Io. outputstream;
Import java. util. enumeration;
Import java. util. properties;

Public class testmain {
 
// Read value based on key
Public static string readvalue (string filepath, string key ){
Properties props = new properties ();
Try {
Inputstream in = new bufferedinputstream (New fileinputstream (filepath ));
Props. Load (in );
String value = props. getproperty (key );
System. Out. println (Key + value );
Return value;
} Catch (exception e ){
E. printstacktrace ();
Return NULL;
}
}
 
// Read all properties information
Public static void readproperties (string filepath ){
Properties props = new properties ();
Try {
Inputstream in = new bufferedinputstream (New fileinputstream (filepath ));
Props. Load (in );
Enumeration en = props. propertynames ();
While (EN. hasmoreelements ()){
String key = (string) en. nextelement ();
String property = props. getproperty (key );
System. Out. println (Key + property );
}
} Catch (exception e ){
E. printstacktrace ();
}
}

// Write Properties Information
Public static void writeproperties (string filepath, string parametername, string parametervalue ){
Properties prop = new properties ();
Try {
Inputstream FCM = new fileinputstream (filepath );
// Read the attribute list (key and element pair) from the input stream)
Prop. Load (FS );
// Call the hashtable method put. Use the getproperty method to provide parallelism.
// The attribute key and value must use a string. The returned value is the result of calling put by hashtable.
Outputstream Fos = new fileoutputstream (filepath );
Prop. setproperty (parametername, parametervalue );
// Use a format suitable for loading data to the properties table using the load method,
// Write the attribute list (key and element pair) in the properties table to the output stream.
Prop. Store (FOS, "Update'" + parametername + "'value ");
} Catch (ioexception e ){
System. Err. println ("visit" + filepath + "for updating" + parametername + "value error ");
}
}

Public static void main (string [] ARGs ){
Readvalue ("info. properties", "url ");
Writeproperties ("info. properties", "Age", "21 ");
Readproperties ("info. properties ");
System. Out. println ("OK ");
}
}