J2ME通过URL访问XML文件并下载XML到本地

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（叶全府）J2ME通过URL访问XML文件并下载XML到本地

2009-06-11 14:45

**
     * 网络连接
     * 固定URL的网络连接
     * @param cmnet
     *            true走cmnet false走cmwap
     * @return返回String类型的XML数据
     */
    private String connect(boolean cmnet) {

        try {
            if (cmnet) {

                http = (HttpConnection) Connector
                        .open(http://xx.cn/t.xml);

            } else {
                http = (HttpConnection) Connector
                        .open(http://10.0.0.3/t.xml);
                http.setRequestProperty("X-Online-Host", "xx.cn");
            }

            http.setRequestProperty("Content-Type", "application/octet-stream");
            http.setRequestProperty("Connection", "Keep-Alive");
            http.setRequestMethod(HttpConnection.GET);

            // 判断是否为连接网络收费提示页面
            String content_type = http.getHeaderField("Content-Type");
            // 如果是返回移动的拦截页面，则重发．
            if (content_type.indexOf("wml") != -1) {
                try {
                    http.close();
                } catch (IOException e) {
                }
                http = null;
                // 重新发起一次请求

                if (cmnet) {
                    http = (HttpConnection) Connector
                            .open(http://xx.cn/t.xml);
                } else {
                    http = (HttpConnection) Connector
                            .open(http://10.0.0.3/t.xml);
                    http.setRequestProperty("X-Online-Host",
                            "xx.cn");
                }
                http.setRequestMethod(HttpConnection.GET);

            }
            int code = http.getResponseCode();

            if (code == 200) {// 返回200 表示连接成功

                // 打开输入流，读取数据
                InputStreamReader is = new InputStreamReader(http
                        .openInputStream(), "UTF-8");
                // 建一StringBuffer，用于保存已读的数据
                StringBuffer sb = new StringBuffer();
                // 每次读取1K的数据
                char[] c = new char[1024];
                int k;
                // 循环读取数据，直到读完当返回-1时表示流已读完
                while ((k = is.read(c)) != -1) {
                    sb.append(c, 0, k);
                }

                is.close();
                is = null;
                http.close();
                http = null;
                return sb.toString();
            }
        } catch (Exception e) {
            e.printStackTrace();
            // return null;
        } finally {

            if (http != null) {
                try {
                    http.close();
                    http = null;
                } catch (IOException e) {
                }
                http = null;
            }
        }

        return null;
    }