这两天在做http服务端请求操作，客户端post数据到服务端后，服务端通过request.getParameter()进行请求，无法读取到数据，搜索了一下发现是因为设置为text/plain模式才导致读取不到数据
urlConn.setRequestProperty("Content-Type","text/plain; charset=utf-8");
若设置为以下方式，则通过request.getParameter()可以读取到数据
urlConn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
enctype的三种编码
form表单中enctype属性可以用来控制对表单数据的发送前的如何进行编码，即在发送到服务器之前，所有字符都会进行编码(空格转换为 "+" 加号，特殊符号转换为 ASCII HEX 值)。默认是application/x-www-form-urlencoded。
multipart/form-data用于发送二进制的文件，其他两种类型不能用于发送文件
text/plain用于发送纯文本内容，不对特殊字符进行编码，一般用于email之类的。
application/x-www-form-urlencoded和text/plain的区别简单讲就是一个发送html内容，一个发送纯文本内容
application/x-www-form-urlencoded 在发送前编码所有字符(默认)
multipart/form-data 不对字符编码。在使用包含文件上传控件的表单时，必须使用该值。
text/plain 空格转换为 "+" 加号，但不对特殊字符编码。
当定义enctype为application/x-www-form-urlencoded时，使用以下方式接收数据
request.getParameter(参数名);
当定义enctype为text/plain时，使用以下方式接收数据
// 接收请求数据
BufferedReader reader = request.getReader();
char[] buf = new char[512];
int len = 0;
StringBuffer contentBuffer = new StringBuffer();
while ((len = reader.read(buf)) != -1) {
contentBuffer.append(buf, 0, len);
}
String content = contentBuffer.toString();
if(content == null){
content = "";
}
post 与get
post和get可以通过键值对的方式进行参数传输，服务端通过request.getparameter方式进行请求获取数据。
客户端post数据到服务端，服务端接收处理
public class UrlConnection {
@SuppressWarnings("finally")
public static boolean response(String url,String content) {
String line = "";
String message = "";
String returnData = "";
boolean postState = false;
BufferedReader bufferedReader = null;
try {
URL urlObject = new URL(url);
HttpURLConnection urlConn = (HttpURLConnection) urlObject.openConnection();
urlConn.setDoOutput(true);
/*设定禁用缓存*/
urlConn.setRequestProperty("Pragma:", "no-cache");
urlConn.setRequestProperty("Cache-Control", "no-cache");
/*维持长连接*/
urlConn.setRequestProperty("Connection", "Keep-Alive");
/*设置字符集*/
urlConn.setRequestProperty("Charset", "UTF-8");
/*设定输出格式为json*/
urlConn.setRequestProperty("Content-Type", "application/json;charset=utf-8");
/*设置使用POST的方式发送*/
urlConn.setRequestMethod("POST");
/*设置不使用缓存*/
urlConn.setUseCaches(false);
/*设置容许输出*/
urlConn.setDoOutput(true);
/*设置容许输入*/
urlConn.setDoInput(true);
urlConn.connect();
OutputStreamWriter outStreamWriter = new OutputStreamWriter(urlConn.getOutputStream(),"UTF-8");
outStreamWriter.write(content);
outStreamWriter.flush();
outStreamWriter.close();
/*若post失败*/
if((urlConn.getResponseCode() != 200)){
returnData = "{\"jsonStrStatus\":0,\"processResults\":[]}";
message = "发送POST失败！"+ "code="+urlConn.getResponseCode() + "," + "失败消息："+ urlConn.getResponseMessage();
// 定义BufferedReader输入流来读取URL的响应
InputStream errorStream = urlConn.getErrorStream();
if(errorStream != null)
{
InputStreamReader inputStreamReader = new InputStreamReader(errorStream,"utf-8");
bufferedReader = new BufferedReader(inputStreamReader);
while ((line = bufferedReader.readLine()) != null) {
message += line;
}
inputStreamReader.close();
}
errorStream.close();
System.out.println("发送失败！错误信息为："+message);
}else{
/*发送成功返回发送成功状态*/
postState = true;
// 定义BufferedReader输入流来读取URL的响应
InputStream inputStream = urlConn.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream,"utf-8");
bufferedReader = new BufferedReader(inputStreamReader);
while ((line = bufferedReader.readLine()) != null) {
message += line;
}
returnData = message;
inputStream.close();
inputStreamReader.close();
System.out.println("发送POST成功！返回内容为：" + message);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
try {
if (bufferedReader != null) {
bufferedReader.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
return postState;
}
}
/*读取request数据*/
public static String getRequestData(HttpServletRequest request) throws IOException{
BufferedReader reader = request.getReader();
char[] buf = new char[512];
int len = 0;
StringBuffer contentBuffer = new StringBuffer();
while ((len = reader.read(buf)) != -1) {
contentBuffer.append(buf, 0, len);
}
String content = contentBuffer.toString();
if(content == null){
content = "";
}
return content;
}
}
