HttpClient -- HTTP工具

package com.http.demo;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.PrintWriter;import java.io.Reader;import java.net.HttpURLConnection;import java.net.ProtocolException;import java.net.URL;import java.util.HashMap;import java.util.Map;/** * http://www.cnblogs.com/not-NULL/p/5531866.html * http://www.cnblogs.com/loveyakamoz/archive/2011/07/21/2113252.html * HTTP工具 */public class HttpUtil {    /**     * 请求类型： GET     */    public final static String GET  = "GET";    /**     * 请求类型： POST     */    public final static String POST = "POST";    /**     * HttpURLConnection方式 模拟Http Get请求     * @param urlStr请求路径     * @param paramMap 请求参数     */    public static String get(String urlStr, Map<String, String> paramMap) throws Exception {        urlStr = urlStr + "?" + getParamString(paramMap);        HttpURLConnection conn = null;        try {            //创建URL对象            URL url = new URL(urlStr);            //获取URL连接            conn = (HttpURLConnection) url.openConnection();            //设置通用的请求属性            setHttpUrlConnection(conn, GET);            //建立实际的连接            conn.connect();            //获取响应的内容            return readResponseContent(conn.getInputStream());        } finally {            if (null != conn)                conn.disconnect();        }    }    /**     * HttpURLConnection方式 模拟Http Post请求     * @param urlStr请求路径     * @param paramMap请求参数     * @return     */    public static String post(String urlStr, Map<String, String> paramMap) throws Exception {        HttpURLConnection conn = null;        PrintWriter writer = null;        try {            //创建URL对象            URL url = new URL(urlStr);            //获取请求参数            String param = getParamString(paramMap);            //获取URL连接            conn = (HttpURLConnection) url.openConnection();            //设置通用请求属性            setHttpUrlConnection(conn, POST);            //建立实际的连接            conn.connect();            //将请求参数写入请求字符流中            writer = new PrintWriter(conn.getOutputStream());            writer.print(param);            writer.flush();            //读取响应的内容            return readResponseContent(conn.getInputStream());        } finally {            if (null != conn)                conn.disconnect();            if (null != writer)                writer.close();        }    }    /**     * 读取响应字节流并将之转为字符串     * @param in要读取的字节流     */    private static String readResponseContent(InputStream in) throws IOException {        Reader reader = null;        StringBuilder content = new StringBuilder();        try {            reader = new InputStreamReader(in);            char[] buffer = new char[1024];            int head = 0;            while ((head = reader.read(buffer)) > 0) {                content.append(new String(buffer, 0, head));            }            return content.toString();        } finally {            if (null != in)                in.close();            if (null != reader)                reader.close();        }    }    /**     * 设置Http连接属性     * @param connhttp连接     * @return     * @throws ProtocolException     * @throws Exception     */    private static void setHttpUrlConnection(HttpURLConnection conn,                                             String requestMethod) throws ProtocolException {        conn.setRequestMethod(requestMethod);        conn.setRequestProperty("content-encoding", "utf8");        conn.setRequestProperty("accept", "application/json");        conn.setRequestProperty("Accept-Charset", "UTF-8");        conn.setRequestProperty("Accept-Language", "zh-CN");        conn.setRequestProperty("User-Agent",            "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)");        conn.setRequestProperty("Proxy-Connection", "Keep-Alive");        System.out.println(conn.getRequestMethod());        if (null != requestMethod && POST.equals(requestMethod)) {            conn.setDoOutput(true);            conn.setDoInput(true);        }    }    /**     * 将参数转为路径字符串     * @param paramMap 参数     */    private static String getParamString(Map<String, String> paramMap) {        if (null == paramMap || paramMap.isEmpty()) {            return "";        }        StringBuilder builder = new StringBuilder();        for (String key : paramMap.keySet()) {            builder.append("&").append(key).append("=").append(paramMap.get(key));        }        return new String(builder.deleteCharAt(0).toString());    }    public static void main(String[] args) {     String url = "http:www.baidu.com";         Map<String, String> params = new HashMap<>();         /*params.put("name", "jerry");         params.put("age", "18");         params.put("sex", "man");*/         try {             //System.out.println(post(url, params));             System.out.println(get(url,null));         } catch (Exception e) {             e.printStackTrace();         }}}

/**  jar包依赖：

<!-- httpclient --><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpcore</artifactId><version>4.3</version></dependency><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.3</version></dependency><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpmime</artifactId><version>4.3</version></dependency><dependency><groupId>org.apache.geronimo.bundles</groupId><artifactId>commons-httpclient</artifactId><version>3.1_2</version></dependency>

*/