HttpURLConnection和HttpClient的用法
HttpServlet
这里的servlet用上一篇博客中的作为web服务器！
DoGet方法
使用httpservlet中的DoGet方法，与服务器进行数据交互！
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
public class DoGetTest {
public static void main(String[] args) {
try {
//创建url对象
URL url= new URL("http://localhost:8080/MyTomcat/MyServletTest?username=张三&password=123456");
//得到URL连接
URLConnection connection = url.openConnection();
HttpURLConnection httpConnection = (HttpURLConnection) connection;
//设置连接超时时间
httpConnection.setConnectTimeout(3000);
//设置读取超时时间
httpConnection.setReadTimeout(3000);
httpConnection.setRequestMethod("GET");
//设置编码格式
//设置接受的数据类型
httpConnection.setRequestProperty("Accept-charset", "UTF-8");
//设置可以接受序列号的java对象
httpConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
//得到HTTP状态码
int code = httpConnection.getResponseCode();
System.out.println("HTTP状态码："+code);
if(code==HttpURLConnection.HTTP_OK){
//接收到服务器返回的数据
BufferedReader br=new BufferedReader(new InputStreamReader(httpConnection.getInputStream()));
String s = br.readLine();
while(s!=null){
System.out.println(s);
s=br.readLine();
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}运行结果：
DoPost方法
使用httpservlet中的DoPost方法，与服务器进行数据交互！
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
public class DoPostTest {
public static void main(String[] args) {
try {
//创建url对象
URL url= new URL("http://localhost:8080/MyTomcat/MyServletTest");
//得到URL连接
URLConnection connection = url.openConnection();
HttpURLConnection httpConnection = (HttpURLConnection) connection;
//设置连接超时时间
httpConnection.setConnectTimeout(3000);
//设置读取超时时间
httpConnection.setReadTimeout(20000);
//设置编码格式
//设置接受的数据类型
httpConnection.setRequestProperty("Accept-charset", "UTF-8");
//设置可以接受序列号的java对象
httpConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
httpConnection.setRequestMethod("POST");
//设置客户端可以给服务器提交数据，默认为false。POST方法必须设置为true
httpConnection.setDoOutput(true);
//POST方法不允许使用缓存
httpConnection.setUseCaches(false);
String params="username=张三&password=123456";
httpConnection.getOutputStream().write(params.getBytes());
//得到HTTP状态码
int code = httpConnection.getResponseCode();
System.out.println("HTTP状态码："+code);
if(code==HttpURLConnection.HTTP_OK){
//接收到服务器返回的数据
BufferedReader br=new BufferedReader(new InputStreamReader(httpConnection.getInputStream()));
String s = br.readLine();
while(s!=null){
System.out.println(s);
s=br.readLine();
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}运行结果：
与数据库的交互
这里用doPost()方法进行一下测试
在服务器端加入连接数据库的代码：
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import lingzhuo20150812.d2.SQLManager;
/** * Servlet implementation class MyServletTest */
@WebServlet("/MyServletTest")
public class MyServletTest extends HttpServlet {
private static final long serialVersionUID = 1L;
/** * @see HttpServlet#HttpServlet() */
public MyServletTest() {
super();
// TODO Auto-generated constructor stub
}
/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//使用浏览器提交数据默认的编码格式为ISO-8859-1
String username=request.getParameter("username");
String password=request.getParameter("password");
//将得到的数据转换为UTF-8编码格式
username=Encoding.doEncoding(username);
password=Encoding.doEncoding(password);
String s="";
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Connection connection=SQLManager.newInstance().getConnection();
try {
PreparedStatement statement=connection.prepareStatement("select * from register where user_name=? and password=?");
statement.setString(1, username);
statement.setString(2, password);
ResultSet set=statement.executeQuery();
set.last();
int num=set.getRow();
if(num==1){
s="登录成功！";
}else{
s="用户名或密码错误";
}
} catch (SQLException e) {
e.printStackTrace();
}
//让浏览器以UTF-8编码格式进行解析
response.setHeader("Content-type", "text/html;charset=UTF-8");
response.getWriter().append(s);
}
/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}创建管理数据库的类
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class SQLManager {
private Connection connection;
public Connection getConnection() {
return connection;
}
public void setConnection(Connection connection) {
this.connection = connection;
}
private static SQLManager manager;
public static synchronized SQLManager newInstance() {
if (manager == null) {
manager = new SQLManager();
}
return manager;
}
private SQLManager() {
try {
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/class", "root", "123456");
if (!connection.isClosed()) {
Statement sql = connection.createStatement();
sql.execute(
"CREATE TABLE if not exists register (ID int(10) NOT NULL PRIMARY KEY AUTO_INCREMENT,user_Name varchar(30) NOT NULL,password varchar(30) not null)");
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
}运行结果：
将DoPost类中“username=张三”改为“username=zhangsan”，与数据库中用户名对应！
HttpClient
客户端，服务器与数据库
使用HttpClient发送请求、接收响应的一般步骤：
1. 创建生成client的builder，利用builder生成httpclient对象client
2. 创建请求实例，可以在创建实例的时候传入参数URL,也可以用setURI()方法指定URL。如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。
3. 调用HttpClient对象client的execute()发送请求，该方法返回一个HttpResponse对象，该对象包含从服务器返回的所有数据。
4. 调用HttpResponse对象respons的getStatusLine()方法，得到表头，包含状态码。调用getEntity()方法，得到数据的实体，返回一个HttpEntity对象，调用该对象的getContent()方法，即可得到输入流！
GET请求
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.util.concurrent.TimeUnit;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;
public class HttpClientDoGetTest {
public static void main(String[] args) {
//创建生成client的builder
HttpClientBuilder builder=HttpClientBuilder.create();
builder.setConnectionTimeToLive(3000, TimeUnit.MILLISECONDS);
HttpClient client=builder.build();//生成client
//设置为Get方法
HttpGet get = new HttpGet("http://localhost:8080/MyTomcat/MyServletTest?username=lisi&password=123456");
//设置服务器接收后数据的读取方式为utf8
get.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
try {
//执行get方法得到服务器返回的所有数据，在response中
HttpResponse response=client.execute(get);
//httpClient访问服务器返回的表头，包含状态码
StatusLine statusLine = response.getStatusLine();
//得到状态码
int num=statusLine.getStatusCode();
if(num==HttpURLConnection.HTTP_OK){
//得到数据的实体
HttpEntity entity= response.getEntity();
//得到输入流
BufferedReader br = new BufferedReader(new InputStreamReader(entity.getContent()));
String s =br.readLine();
while(s!=null){
System.out.println(s);
s=br.readLine();
}
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}运行结果：
POST请求
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.util.ArrayList;
import java.util.concurrent.TimeUnit;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.message.BasicNameValuePair;
public class HttpClientDoPostTest {
public static void main(String[] args) {
// 创建生成client的builder
HttpClientBuilder builder = HttpClientBuilder.create();
builder.setConnectionTimeToLive(3000, TimeUnit.MILLISECONDS);
HttpClient client = builder.build();// 生成client
HttpPost post = new HttpPost("http://localhost:8080/MyTomcat/MyServletTest");
//如果用户名为中文，则服务器端不需要再转码，因为下边已经封装为UTF-8编码
NameValuePair pair1 = new BasicNameValuePair("username", "zhangsan");
NameValuePair pair2 = new BasicNameValuePair("password", "123456");
ArrayList<NameValuePair> list = new ArrayList<>();
list.add(pair1);
list.add(pair2);
try {
post.setEntity(new UrlEncodedFormEntity(list, "UTF-8"));
post.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
HttpResponse response = client.execute(post);
int code = response.getStatusLine().getStatusCode();
if (code == HttpURLConnection.HTTP_OK) {
BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String s = br.readLine();
while (s != null) {
System.out.println(s);
s = br.readLine();
}
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}运行结果：
