怎么配置Tomcat支持HTTP Delete和Put 方法

如何配置Tomcat支持HTTP Delete和Put 方法
在tomcat web.xml文件中配置org.apache.catalina.servlets.DefaultServlet的

<init-param>     
<param-name>readonly</param-name>    
<param-value>false</param-value>  
</init-param> 

readonly参数默认是true，即不允许delete和put操作，所以通过XMLHttpRequest对象的put或者delete方法访问就会报告http 403错误。为REST服务起见，应该设置该属性为false。

逻辑：

String url = "http://www.baidu.com";

//将要访问的url字符串放入HttpPost中

HttpPost httpPost = new HttpPost(url);

//请求头 放置一些修改http请求头和cookie

httpPost.setHeader("Accept", "application/json");

......

//如果是HttpPost或者HttpPut请求需要在请求里加参数，而HttpGet或者HttpDelete请求则可以直接拼接到url字符串后面

//向HttpPost中加入参数

List<NameValuePair> values = new ArrayList<NameValuePair>();

values.add(new NameValuePair("id", "1"));

values.add(new NameValuePair("name", "xiaohong"));

httpPost.setEntity(new UrlEncodeFormEntity(values, HTTP.UTF_8));  //进行转码

//实例HttpClient 并执行带有HttpPost的方法,返回HttpResponse 响应，再进行操作

HttpClient httpClient = new DefaultHttpClient();

HttpResponse httpResponse = httpClient.execute(httpPost);

int statusCode = httpResponse.getStatusLine().getStatusCode();  //返回状态码 ，用来进行识别或者判断访问结果

if(statusCode == 200){

　　Instream in = httpResponse.getEntity().getContent();  //要处理该数据流是否为GZIP流

}

示例代码如下：

package cn.dratek.haoyingsheng.manager.client;

import cn.dratek.haoyingsheng.manager.util.ResourceUtil;
import net.dratek.browser.http.Cookie;
import net.dratek.browser.http.CookieManager;
import net.dratek.browser.http.URL;
import org.apache.http.*;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HTTP;

import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.List;

public class HttpNetClient {
/**
* 所有get 请求底层调用方法
*
* @param url 请求url
* @return byte[] response data
*/
public static byte[] doGet(String url) {
InputStream in;
byte[] bre = null;
HttpResponse response;
CookieManager manager = CookieManager.getInstance();
if (url != null && url.length() != 0) {
URL myURL = URL.parseString(url);
Cookie[] cookies = manager.getCookies(myURL);
HttpGet httpGet = new HttpGet(url);
if (cookies != null && cookies.length > 0) {
StringBuilder sb = new StringBuilder();
for (Cookie ck : cookies) {
sb.append(ck.name).append('=').append(ck.value).append(";");
}
String sck = sb.toString();
if (sck.length() > 0) {
httpGet.setHeader("Cookie", sck);
}

}
httpGet.setHeader("Accept-Encoding", "gzip, deflate");
httpGet.setHeader("Accept-Language", "zh-CN");
httpGet.setHeader("Accept", "application/json, application/xml, text/html, text/*, image/*, */*");
try {
response = new DefaultHttpClient().execute(httpGet);
if (response != null) {
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode == 200 || statusCode == 403) {
Header[] headers = response.getHeaders("Set-Cookie");
if (headers != null && headers.length > 0) {
for (Header header : headers) {
manager.setCookie(myURL, header.getValue());
}
}
in = response.getEntity().getContent();
if (in != null) {
bre = ResourceUtil.readStream(in);
}

}
}

} catch (IOException e) {
e.printStackTrace();
}
}

return bre;

}

/**
* 所有Post 请求底层调用方法
*
* @param url 请求url
* @param values 传递的参数
* @return byte[] 返回数据 or null
*/
public static byte[] doPost(String url, List<NameValuePair> values) {
System.out.println("url = " + url);
byte[] bytes = null;
HttpResponse response;
InputStream inputStream = null;
CookieManager manager = CookieManager.getInstance();
if (url != null && url.length() != 0) {
URL myurl = URL.parseString(url);
Cookie[] cookies = manager.getCookies(myurl);
HttpPost post = new HttpPost(url);
if (cookies != null && cookies.length > 0) {
StringBuilder sb = new StringBuilder();
for (Cookie ck : cookies) {
sb.append(ck.name).append('=').append(ck.value).append(";");
}
String sck = sb.toString();
if (sck.length() > 0) {
post.setHeader("Cookie", sck);
}

}
post.setHeader("Accept-Encoding", "gzip, deflate");
post.setHeader("Accept-Language", "zh-CN");
post.setHeader("Accept", "application/json, application/xml, text/html, text/*, image/*, */*");
DefaultHttpClient client = new DefaultHttpClient();
try {
if (values != null && values.size() > 0) {
post.setEntity(new UrlEncodedFormEntity(values, HTTP.UTF_8));
}
response = client.execute(post);
if (response != null) {
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode == 200 || statusCode == 403) {
Header[] headers = response.getHeaders("Set-Cookie");
if (headers != null && headers.length > 0) {
for (Header header : headers) {
manager.setCookie(myurl, header.getValue());
}
}
inputStream = response.getEntity().getContent();
}
}

} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (inputStream != null) {
bytes = ResourceUtil.readStream(inputStream);
}
}
return bytes;
}

/**
* PUT基础请求
*
* @param url 请求地址
* @param values 提交参数
* @return byte[] 请求成功后的结果
*/
public static byte[] doPut(String url, List<NameValuePair> values) {
byte[] ret = null;

CookieManager manager = CookieManager.getInstance();
if (url != null && url.length() > 0) {
URL myUrl = URL.parseString(url);
StringBuilder sb = new StringBuilder();
Cookie[] cookies = manager.getCookies(myUrl);
if (cookies != null && cookies.length > 0) {
for (Cookie cookie : cookies) {
sb.append(cookie.name).append("=").append(cookie.value).append(";");
}

}
HttpPut request = new HttpPut(url);
String sck = sb.toString();
if (sck.length() > 0) {
request.setHeader("Cookie", sck);
}
request.setHeader("Accept-Encoding", "gzip, deflate");
request.setHeader("Accept-Language", "zh-CN");
request.setHeader("Accept", "application/json, application/xml, text/html, text/*, image/*, */*");

DefaultHttpClient client = new DefaultHttpClient();
if (values != null && values.size() > 0) {
try {
UrlEncodedFormEntity entity;
entity = new UrlEncodedFormEntity(values);
request.setEntity(entity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
try {
HttpResponse response = client.execute(request);
if (response != null) {
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200 || statusCode == 403) {
Header[] headers = response.getHeaders("Set-Cookie");
if (headers != null && headers.length > 0) {
for (Header header : headers) {
manager.setCookie(myUrl, header.getValue());
}
}
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();
if (inputStream != null) {
ret = ResourceUtil.readStream(inputStream);
inputStream.close();
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
return ret;
}

/**
* Delete基础请求
*
* @param url 请求地址
* @return 请求成功后的结果
*/
public static byte[] doDelete(String url) {

InputStream in;
byte[] bre = null;
HttpResponse response;
CookieManager manager = CookieManager.getInstance();
if (url != null && url.length() != 0) {
URL myurl = URL.parseString(url);
Cookie[] cookies = manager.getCookies(myurl);
HttpDelete delete = new HttpDelete(url);
if (cookies != null && cookies.length > 0) {
StringBuilder sb = new StringBuilder();
for (Cookie ck : cookies) {
sb.append(ck.name).append('=').append(ck.value).append(";");
}
String sck = sb.toString();
if (sck.length() > 0) {
delete.setHeader("Cookie", sck);
}

}
delete.setHeader("Accept-Encoding", "gzip, deflate");
delete.setHeader("Accept-Language", "zh-CN");
delete.setHeader("Accept", "application/json, application/xml, text/html, text/*, image/*, */*");
try {
response = new DefaultHttpClient().execute(delete);
if (response != null) {
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode == 200 || statusCode == 403) {
Header[] headers = response.getHeaders("Set-Cookie");
if (headers != null && headers.length > 0) {
for (Header header : headers) {
manager.setCookie(myurl, header.getValue());
}
}
in = response.getEntity().getContent();
if (in != null) {
bre = ResourceUtil.readStream(in);
}

}
}

} catch (IOException e) {
e.printStackTrace();
}
}

return bre;
}

}

J2EE中最大的一个观念就是分层.. 

session是持久层的东东.不可窜到别的层.. 

你的这个问题其实就是延迟加载的问题. 

从理论的角度讲,最好是用一个就关一个.防止资源消耗. 
但由于hibernate中的延迟加载,所以出现了你的关闭session的话,就无法读取到学生类里的classes值问题. 
这个问题可以用Hibernate.initialize()来解决.也可就使用opensessionview的方式.spring中提供了这样的filter 
不知道这在使用中有没有使用spring.用了就比较方便,也不会出现你所说的 

package com.abin.lee.hack;

import java.io.BufferedInputStream;

import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.junit.Test;

public class HttpClientVisitTest {

 private static final String HttpUrl = "http://111.111.111.111/vote/ticket";
 private static final String HttpHost = "111.111.111.111";
 @Test
 public void testHttpClientVisit() {
  HttpClient httpClient = new DefaultHttpClient();
  HttpPost httpPost = new HttpPost(HttpUrl);
  httpPost.addHeader("Accept", "*/*");
  httpPost.addHeader("Accept-Language", "zh-cn");
  httpPost.addHeader("Referer", HttpUrl);
  httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
  httpPost.addHeader("Cache-Control", "no-cache");
  httpPost.addHeader("Accept-Encoding", "gzip, deflate");
  httpPost.addHeader("User-Agent",
    "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)");
  httpPost.addHeader("Host", HttpHost);
  httpPost.addHeader("Connection", "Keep-Alive");
//  HttpHost httpProxy = new HttpHost("222.222.222.222", 1443, "http");
//  httpClient.getParams().setParameter(AllClientPNames.DEFAULT_PROXY,httpProxy);
  StringBuffer params = new StringBuffer();
  String userName = "abin";
  String passWord= "varyall";
  String userAge= "12345";
  String homeTown= "china beijing";
  params.append("__userName ").append("=").append(userName )
    .append("&").append(passWord").append("=")
    .append(passWord).append("&").append("userAge")
    .append("=").append(userAge).append("&")
    .append("homeTown").append("=")
    .append(homeTown);
  HttpResponse httpResponse = null;
  String result = "";
  try {
   StringEntity reqEntity = new StringEntity(params.toString());
   httpPost.setEntity(reqEntity);
   HttpHost httpTarget = new HttpHost(HttpHost, 80, "http");
   httpResponse = httpClient.execute(httpTarget, httpPost);
   System.out.println("httpResponse=" + httpResponse.getStatusLine());

   BufferedInputStream buffer = new BufferedInputStream(httpResponse
     .getEntity().getContent());
   byte[] bytes = new byte[1024];
   int line = 0;
   StringBuilder builder = new StringBuilder();
   while ((line = buffer.read(bytes)) != -1) {
    builder.append(new String(bytes, 0, line));
   }
   result = new String(builder.toString());
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   if (httpPost.isAborted()) {
    httpPost.abort();
   }
   httpClient.getConnectionManager().shutdown();
  }
//   System.out.println("result="+result);

 }

}