JspWriter and PrintWriter (turn)

1 Inherit from Java.io.writer class

JspWriter directly with the Out object on the JSP page, or you can get the out object directly with Pagecontex.getout ()

PrintWriter must be obtained by Response.getwriter ()

2. In the JSP page in two ways to output data at the same time, the data in the PrintWriter will first output

For example:

New Test.jsp Page

<%
Out.println ("Out");
JspWriter out1 = Pagecontext.getout ();
if (out = = OUT1)
{
Out.println ("out==out1");
}
Else
{
Out.println ("out!=out1");
}

PrintWriter pw = Response.getwriter ();
Pw.write ("pw Writer");
%>

Run the result as

PW writer Out out==out1 The is my JSP page.

Reason:

The Out object is equivalent to inserting into a buffer in front of PrintWriter. When an out object satisfies a certain condition

, the print () method of the PrintWriter object is called to output the contents of the out buffer to the browser side

If you want to make the above code sequential output in code, you can write it as follows:

Out.flush ();

Refresh the buffer to

The output turns into

Out OUT==OUT1 pw Writer This is my JSP page

In addition: The PrintWriter Print method does not throw IOException, and JspWriter will.
JspWriter is an abstract class and PrintWriter is not, which means that you can create a new PrintWriter object directly by using the new operation and JspWriter not, it must be created by its subclass.
But they are also related, the relationship is mainly jspwriter to printwriter dependence. When initializing a JspWriter object, a PrintWriter object of the Servletresponse object is associated, and the output of the final JspWriter object is made by this PrintWriter type object.

JspWriter and PrintWriter (turn)