这节课我们来讲HttpServletResponse接口
public interface HttpServletResponse extends ServletResponse
可以看到HttpServletResponse接口是ServletResponse的子接口
里面有很多方法，就不细讲了，反正也不常用
说下HttpServletResponse的作用:
- 可以通过HttpServletResponse对象获取PrintWriter后向页面输出数据
- 重定向
HttpServletResponseTeachServlet.java
package com.servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
/**
* HttpServletResponse的作用:
* 1.可以通过HttpServletResponse对象获取PrintWriter后向页面输出数据
* 2.重定向
*/
public class HttpServletResponseTeachServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String url = req.getRequestURL().toString();
if (url.endsWith("/printWriter"))
{
printWriterTeach(req,resp);
}
if (url.endsWith("/redirect"))
{
redirectTeach(req,resp);
}
if (url.endsWith("/123"))
{
System.out.println("重定向到请求 /123");
}
}
private void printWriterTeach(HttpServletRequest req, HttpServletResponse resp) {
PrintWriter writer = null;
try {
//这个是设置字符编码
//不过过滤器应该已经过滤好了
resp.setCharacterEncoding("UTF-8");
writer = resp.getWriter();
writer.write("<a href='http://www.oschina.net'>开源中国</a>");
//Chrome默认编码好像是gbk，我等会去设置一下
//360浏览器可以自动检测出UTF-8编码
} catch (IOException e) {
e.printStackTrace();
}finally {
if (writer != null)
writer.close();
}
}
private void redirectTeach(HttpServletRequest req, HttpServletResponse resp) {
try {
resp.sendRedirect("/123");
//重定向: 向服务器发起新的请求，且浏览器地址栏变成重定向请求的url
} catch (IOException e) {
e.printStackTrace();
}
}
}
web.xml
<servlet>
<servlet-name>ResponseServlet</servlet-name>
<servlet-class>com.servlet.HttpServletResponseTeachServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ResponseServlet</servlet-name>
<url-pattern>/printWriter</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ResponseServlet</servlet-name>
<url-pattern>/redirect</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ResponseServlet</servlet-name>
<url-pattern>/123</url-pattern>
</servlet-mapping>
