一般在*.html,*.jsp页面中我们通过使用ajax调用接口,这个是我们通常用的。对于这些接口，大都是本公司写的接口供自己调用，所以直接用ajax就可以。但是，如果是多家公司共同开发一个东西，一个功能可能要调多个接口，一两个ajax可以在jsp页面上显示,但是如果多了,就不能写这么多ajax在前端了。这时候需要封装一成一个接口，在接口里面如何调用其他接口呢？这就用到了java.net.URL这个类。
java.net.URL用法如下
BufferedReader in=null;
java.net.HttpURLConnection conn=null;
String msg = "";// 保存调用http服务后的响应信息
try
{
//实例化url
java.net.URL url = new java.net.URL(path);
//根据url获取HttpURLConnection
conn = (java.net.HttpURLConnection) url.openConnection();
//设置请求的参数
conn.setRequestMethod("POST");
conn.setConnectTimeout(5 * 1000);// 设置连接超时时间为5秒
conn.setReadTimeout(20 * 1000);// 设置读取超时时间为20秒
conn.setDoOutput(true); // 使用 URL 连接进行输出，则将 DoOutput标志设置为 true
conn.setDoInput(true);
conn.setRequestProperty("Content-Type", "text/xml;charset=UTF-8");
//conn.setRequestProperty("Content-Encoding","gzip");
conn.setRequestProperty("Content-Length", String.valueOf(params.length())); //设置请求内容(长度)长度
OutputStream outStream = conn.getOutputStream(); // 返回写入到此连接的输出流
outStream.write(params.getBytes()); //将参数写入流中
outStream.close();//关闭流 if (conn.getResponseCode() == 200) {
// HTTP服务端返回的编码是UTF-8,故必须设置为UTF-8,保持编码统一,否则会出现中文乱码
in = new BufferedReader(new InputStreamReader((InputStream) conn.getInputStream(), "UTF-8"));
msg = in.readLine();
}
}catch(Exception ex)
{
ex.printStackTrace();
}finally
{
if(null!=in)
{
in.close();
}
if(null!=conn)
{
conn.disconnect();
}
}
return msg;
HttpUtil工具类
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream; import java.net.HttpURLConnection;
import java.net.URL; /**
* http工具
*
*/
public final class HttpUtil {
/**
* 模拟http协议发送get请求
**/
public static String sendGetRequest(String url) {
String result = "";
InputStream in = null; HttpURLConnection connection = null; try {
URL httpUrl = new URL(url);
connection = (HttpURLConnection) httpUrl.openConnection();
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("Charset", "UTF-8");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
connection.setRequestMethod("GET");
connection.connect(); if (connection.getResponseCode() == 200) {
in = connection.getInputStream(); ByteArrayOutputStream bs = new ByteArrayOutputStream();
int n = 0;
byte[] datas = new byte[2048]; while ((n = in.read(datas)) != -1) {
bs.write(datas, 0, n);
} bs.flush();
result = new String(bs.toByteArray(), "utf-8");
}
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
if (in != null) {
in.close();
}
} catch (Exception e) {
e.printStackTrace();
} try {
connection.disconnect();
} catch (Exception ex) {
}
} return result;
} /**
* 模拟http协议发送post请求
**/
public static String sendPostRequest(String url, String param) {
InputStream in = null;
String result = "";
HttpURLConnection connection = null; try {
URL httpUrl = new URL(url);
connection = (HttpURLConnection) httpUrl.openConnection();
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("Charset", "UTF-8");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.getOutputStream().write(param.getBytes("utf-8"));
connection.getOutputStream().flush(); if (connection.getResponseCode() == 200) {
in = connection.getInputStream(); ByteArrayOutputStream bs = new ByteArrayOutputStream();
int n = 0;
byte[] datas = new byte[2048]; while ((n = in.read(datas)) != -1) {
bs.write(datas, 0, n);
} bs.flush();
result = new String(bs.toByteArray(), "utf-8");
}
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
if (in != null) {
in.close();
}
} catch (IOException ex) {
ex.printStackTrace();
} try {
connection.disconnect();
} catch (Exception ex) {
}
} return result;
} /**
* 普通post文件上传
*/
public static String upLoadAttachment(String url, String fileName, File file) {
String result = null; HttpURLConnection connection = null;
BufferedReader reader = null; try {
URL httpUrl = new URL(url);
connection = (HttpURLConnection) httpUrl.openConnection();
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("Charset", "UTF-8");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
connection.setRequestMethod("POST");
connection.setConnectTimeout(5000);
connection.setReadTimeout(5000);
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false); String bound = "----------" + System.currentTimeMillis();
connection.setRequestProperty("Content-Type",
"multipart/form-data; boundary=" + bound); StringBuilder sb = new StringBuilder();
sb.append("--");
sb.append(bound);
sb.append("\r\n");
sb.append("Content-Disposition: form-data;name=\"" + fileName +
"\";filename=\"" + file.getName() + "\"\r\n");
sb.append("Content-Type:application/octet-stream\r\n\r\n"); byte[] data = sb.toString().getBytes("utf-8");
OutputStream out = new DataOutputStream(connection.getOutputStream());
out.write(data); DataInputStream in = new DataInputStream(new FileInputStream(file));
int bytes = 0;
byte[] bufferOut = new byte[1024]; while ((bytes = in.read(bufferOut)) != -1) {
out.write(bufferOut, 0, bytes);
} in.close(); byte[] foot = ("\r\n--" + bound + "--\r\n").getBytes("utf-8"); // 定义最后数据分隔线
out.write(foot);
out.flush();
out.close(); InputStream inn = connection.getInputStream();
ByteArrayOutputStream bs = new ByteArrayOutputStream();
int n = 0;
byte[] datas = new byte[2048]; while ((n = inn.read(datas)) != -1) {
bs.write(datas, 0, n);
} bs.flush();
result = new String(bs.toByteArray(), "utf-8"); return result;
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
connection.disconnect();
} catch (Exception ex) {
}
} return null;
} /**
* post文件上传 - 使用InputStream输入流(例如MultipartFile从前端获取文件后转发给其他的服务器)
*/
public static String upLoadAttachment(String url,String keyName, String fileName, InputStream fins) {
String result = null; HttpURLConnection connection = null;
BufferedReader reader = null; try {
URL httpUrl = new URL(url);
connection = (HttpURLConnection) httpUrl.openConnection();
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("Charset", "UTF-8");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
connection.setRequestMethod("POST");
connection.setConnectTimeout(5000);
connection.setReadTimeout(5000);
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false); String bound = "----------" + System.currentTimeMillis();
connection.setRequestProperty("Content-Type",
"multipart/form-data; boundary=" + bound); StringBuilder sb = new StringBuilder();
sb.append("--");
sb.append(bound);
sb.append("\r\n");
sb.append("Content-Disposition: form-data;name=\"" + keyName +
"\";filename=\"" + fileName + "\"\r\n");
sb.append("Content-Type:application/octet-stream\r\n\r\n"); byte[] data = sb.toString().getBytes("utf-8");
OutputStream out = new DataOutputStream(connection.getOutputStream());
out.write(data); DataInputStream in = new DataInputStream(fins);
int bytes = 0;
byte[] bufferOut = new byte[1024]; while ((bytes = in.read(bufferOut)) != -1) {
out.write(bufferOut, 0, bytes);
} in.close(); byte[] foot = ("\r\n--" + bound + "--\r\n").getBytes("utf-8"); // 定义最后数据分隔线
out.write(foot);
out.flush();
out.close(); InputStream inn = connection.getInputStream();
ByteArrayOutputStream bs = new ByteArrayOutputStream();
int n = 0;
byte[] datas = new byte[2048]; while ((n = inn.read(datas)) != -1) {
bs.write(datas, 0, n);
} bs.flush();
result = new String(bs.toByteArray(), "utf-8"); return result;
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
connection.disconnect();
} catch (Exception ex) {
}
} return null;
}
}