Q&A : How can I write primitive data-types?

Question

How can I write primitive data-types to disk? In C/C++, the printf statement could write integers, floats, as well as other types.

Answer

Writing primitive data-types can be easily done, using the DataOutputStream class. DataOutputStream provides simple methods to write primitive data-types out to any output stream, whether it be the user console, a network connection, or a file.

Data Type	Method
boolean	writeBoolean(boolean v);
byte	writeByte(int v); writeBytes(String s);
char, string	writeChar(int v); writeChars(String s);
double	writeDouble(double v);
float	writeFloat(float v);
int	writeInt(int v);
long	writeLong(long v);
short	writeShort(int v);
string	writeUTF(String str);

Figure 1.0 - Methods of DataOutputStream

Java also provides a corresponding DataInputStream, which will allow you to read data back. This means you can write a data structure out to a disk or network connection, and read it back at a later date.

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