servlet里面没有printWriter如何解决
时间: 2024-10-18 17:22:22 浏览: 34
在Servlet中如果没有使用`PrintWriter`,通常是为了避免直接向客户端响应体写入文本,因为`PrintWriter`会自动添加额外的头信息,如Content-Type等。如果需要控制响应内容,可以使用`ServletResponse.getWriter()`方法获取`OutputStream`或`BufferedOutputStream`,然后通过`OutputStreamWriter`或者更高级的`StringWriter`配合`BufferedReader`来处理字符串。
例如:
```java
response.setContentType("text/plain");
OutputStream outputStream = response.getOutputStream();
BufferedOutputStream bufferedOut = new BufferedOutputStream(outputStream);
StringWriter writer = new StringWriter();
// 使用writer写入数据
writer.write("Hello, Server!");
bufferedOut.write(writer.toString().getBytes());
bufferedOut.flush();
```
或者,如果你只需要返回简单的字符串,可以直接从`String`构造`HttpServletResponse`的`OutputStream`,如下所示:
```java
String message = "Hello";
response.setContentType("text/plain");
response.getWriter().write(message);
```
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大致讲解一下代码:6.BuyPhoneServlet: package Session01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayList; @WebServlet("/buyPhoneServlet") public class BuyPhoneServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); PrintWriter out=resp.getWriter(); String idstr=req.getParameter("id"); int id=Integer.parseInt(idstr); ArrayList ckDB= PhoneDb.getAll(); Phone ck=ckDB.get(id-1); out.println("您购买的"+ck.getName()+"手机下单成功。"); out.println("继续选购"); } }




