SetDoOutput()到底会影响什么？

URLConnection里有 setDoOutput()根据 文件我应该

如果打算使用 URL 连接进行输出，则将 DoOutput 标志设置为 true，如果不设置，则设置为 false。

现在我面对的是 正是这个问题—— Java 运行时在调用 setDoOutput(true)时将请求转换为 POST，而服务器只响应 GET请求。我想知道如果从代码中删除 setDoOutput(true)会发生什么。

这究竟会影响到什么？假设我把它设置为 false-我现在能做什么，不能做什么？我能够执行 GET请求吗？在这个方法的上下文中，什么是“输出”？

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setDoOutput(true) is used for POST and PUT requests. If it is false then it is for using GET requests.

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public void setDoOutput( boolean dooutput )

It takes a value as the parameter and sets this value of the doOutput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoOutput flag to true if you intend to use the URL connection for output, false if not. The default is false.

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最佳答案

You need to set it to true if you want to send (output) a request body, for example with POST or PUT requests. With GET, you do not usually send a body, so you do not need it.

Sending the request body itself is done via the connection's output stream:

conn.getOutputStream().write(someBytes);
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Adding a comment, if you have a long lasting connection and you send both GETs and POSTs, this is what I do:

if (doGet) {    // some boolean
con.setDoOutput(false); // reset any previous setting, if con is long lasting
con.setRequestMethod("GET");
}
else {
con.setDoOutput(true);  // reset any previous setting, if con is long lasting
con.setRequestMethod("POST");
}

And to avoid making the connection long lasting, close it each time.

if (doClose)    // some boolean
con.setRequestProperty("Connection", "close");


con.connect();              // force connect request

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