無論是用哪種方式使Android與web后台進行數據交互，都需要在eclipes中寫一個完整的操作流程，在這里，我是寫了一個登錄。（沒有從數據庫進行判斷，而是直接把用戶名和密碼定死了），下面就是我的后台web端。你可以根據你的不同需求在jsp界面用你所需要的提交方式來寫
login,jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- <form action="login.do" method="get">
用戶名：<input type="text" name="uname"/><br>
密碼：<input type="password" name="upass"/><br>
<input type="submit" value="登錄"/>
</form> -->
<form action="login.do" method="post">
用戶名：<input type="text" name="uname"/><br>
密碼：<input type="password" name="upass"/><br>
<input type="submit" value="登錄"/>
</form>
</body>
</html>
LoginServlet:
package com.lxj.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Login extends HttpServlet{
// @Override
// protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// String uname=req.getParameter("uname");
// String upass=req.getParameter("upass");
//
// String a=null;
// if("admin".equals(uname) && "123".equals(upass)){
// a="succes";
// System.out.println(a);
// }else{
// a="fail";
// System.out.println(a);
// }
// PrintWriter pw=resp.getWriter();
// pw.write(a);
// pw.close();
// }
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String uname=req.getParameter("uname");
String upass=req.getParameter("upass");
String a=null;
if("admin".equals(uname) && "123".equals(upass)){
a="succes";
System.out.println(a);
}else{
a="fail";
System.out.println(a);
}
PrintWriter pw=resp.getWriter();
pw.write(a);
pw.close();
}
}
最后，還要記得在web.xml里面配置跳轉路徑
<servlet>
<servlet-name>login</servlet-name>
<servlet-class>com.lxj.servlet.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>
第一：GET提交方式:
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.android_getandpost.MainActivity">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="請輸入用戶名"
android:id="@+id/uname"
/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="請輸入密碼"
android:id="@+id/upass"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="登陸(Get)"
android:onClick="LoginGet"
/>
</LinearLayout>
MainActivity:
package com.example.android_getandpost;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class MainActivity extends AppCompatActivity {
private EditText uname;
private EditText upass;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//獲取用戶名的id
uname = (EditText) findViewById(R.id.uname);
//獲取密碼的id
upass = (EditText) findViewById(R.id.upass);
}
public void LoginGet(View view){
//獲取用戶名的值
String name=uname.getText().toString();
//獲取密碼的值
String pass=upass.getText().toString();
//獲取網絡上的servlet路徑
String path="http://193.168.3.16:8080/Login/login.do";
//調用getTask,把獲取到的用戶名，密碼與路徑放入方法中
new getTask().execute(name,pass,path);
}
class getTask extends AsyncTask {
@Override
protected Object doInBackground(Object[] params) {
//依次獲取用戶名，密碼與路徑
String name = params[0].toString();
String pass = params[1].toString();
String path = params[2].toString();
try {
//獲取網絡上get方式提交的整個路徑
URL url = new URL(path + "?uname=" + name + "&upass=" + pass);
//打開網絡連接
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//設置提交方式
conn.setRequestMethod("GET");
//設置網絡超時時間
conn.setConnectTimeout(5000);
//獲取結果碼
int code = conn.getResponseCode();
if (code == 200) {
//用io流與web后台進行數據交互
InputStream is = conn.getInputStream();
//字節流轉字符流
BufferedReader br = new BufferedReader(new InputStreamReader(is));
//讀出每一行的數據
String s = br.readLine();
//返回讀出的每一行的數據
return s;
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
//獲取Android studio與web后台數據交互獲得的值
String s= (String) o;
//吐司Android studio與web后台數據交互獲得的值
Toast.makeText(MainActivity.this, s, Toast.LENGTH_SHORT).show();
}
}
}
第二：POST提交方式：
activity_main2.xml:
package com.example.android_getandpost;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class MainActivity extends AppCompatActivity {
private EditText uname;
private EditText upass;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//獲取用戶名的id
uname = (EditText) findViewById(R.id.uname);
//獲取密碼的id
upass = (EditText) findViewById(R.id.upass);
}
public void LoginGet(View view){
//獲取用戶名的值
String name=uname.getText().toString();
//獲取密碼的值
String pass=upass.getText().toString();
//獲取網絡上的servlet路徑
String path="http://193.168.3.16:8080/Login/login.do";
//調用getTask,把獲取到的用戶名，密碼與路徑放入方法中
new getTask().execute(name,pass,path);
}
class getTask extends AsyncTask {
@Override
protected Object doInBackground(Object[] params) {
//依次獲取用戶名，密碼與路徑
String name = params[0].toString();
String pass = params[1].toString();
String path = params[2].toString();
try {
//獲取網絡上get方式提交的整個路徑
URL url = new URL(path + "?uname=" + name + "&upass=" + pass);
//打開網絡連接
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//設置提交方式
conn.setRequestMethod("GET");
//設置網絡超時時間
conn.setConnectTimeout(5000);
//獲取結果碼
int code = conn.getResponseCode();
if (code == 200) {
//用io流與web后台進行數據交互
InputStream is = conn.getInputStream();
//字節流轉字符流
BufferedReader br = new BufferedReader(new InputStreamReader(is));
//讀出每一行的數據
String s = br.readLine();
//返回讀出的每一行的數據
return s;
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
//獲取Android studio與web后台數據交互獲得的值
String s= (String) o;
//吐司Android studio與web后台數據交互獲得的值
Toast.makeText(MainActivity.this, s, Toast.LENGTH_SHORT).show();
}
}
}
Main2Activity:
package com.example.android_getandpost;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class Main2Activity extends AppCompatActivity {
private EditText upass;
private EditText uname;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
//獲取用戶名的id
uname = (EditText) findViewById(R.id.uname);
//獲取密碼的id
upass = (EditText) findViewById(R.id.upass);
}
public void LoginPost(View view){
//獲取用戶名的值
String name=uname.getText().toString();
//獲取密碼的值
String pass=upass.getText().toString();
//獲取網絡上的servlet路徑
String path="http://193.168.3.16:8080/Login/login.do";
//調用postTask,把獲取到的用戶名，密碼與路徑放入方法中
new postTask().execute(name,pass,path);
}
class postTask extends AsyncTask{
@Override
protected Object doInBackground(Object[] params) {
//依次獲取用戶名，密碼與路徑
String name=params[0].toString();
String pass=params[1].toString();
String path=params[2].toString();
try {
//獲取網絡上get方式提交的整個路徑
URL url=new URL(path);
//打開網絡連接
HttpURLConnection conn= (HttpURLConnection) url.openConnection();
//設置提交方式
conn.setRequestMethod("POST");
//設置網絡超時時間
conn.setConnectTimeout(5000);
//界面上所有的參數名加上他的值
String s="uname="+name+"&upass"+pass;
//獲取請求頭
conn.setRequestProperty("Content-Length",s.length()+"");//鍵是固定的
conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");//鍵和值是固定的
//設置允許對外輸出數據
conn.setDoOutput(true);
//把界面上的所有數據寫出去
OutputStream os=conn.getOutputStream();
os.write(s.getBytes());
if(conn.getResponseCode()==200){
//用io流與web后台進行數據交互
InputStream is=conn.getInputStream();
//字節流轉字符流
BufferedReader br=new BufferedReader(new InputStreamReader(is));
//讀出每一行的數據
String str=br.readLine();
//返回讀出的每一行的數據
return str;
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
//獲取Android studio與web后台數據交互獲得的值
String s= (String) o;
//吐司Android studio與web后台數據交互獲得的值
Toast.makeText(Main2Activity.this, s, Toast.LENGTH_SHORT).show();
}
}
}
第三：運用第三方（android-async-http-1.4.4.jar）：
首先，在項目中把jar包導入libs,然后右擊選擇add as library解壓，再在build.gradle中的
compileSdkVersion 25
buildToolsVersion "25.0.2"上面加上這樣一句代碼：useLibrary 'org.apache.http.legacy'，然后編譯
以解決HttpClient導致不可以問題
activity_mian3.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.android_getandpost.Main3Activity">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="請輸入用戶名"
android:id="@+id/uname"
/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="請輸入密碼"
android:id="@+id/upass"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="登陸(AsyncHttpClient)"
android:onClick="LoginAsyncHttpClient"
/>
</LinearLayout>
Main3Activity：
package com.example.android_getandpost;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.RequestHandle;
import com.loopj.android.http.RequestParams;
import com.loopj.android.http.TextHttpResponseHandler;
import org.apache.http.Header;
public class Main3Activity extends AppCompatActivity {
private EditText upass;
private EditText uname;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main3);
//獲取用戶名的id
uname = (EditText) findViewById(R.id.uname);
//獲取密碼的id
upass = (EditText) findViewById(R.id.upass);
}
public void LoginAsyncHttpClient(View view){
//獲取用戶名的值
String name=uname.getText().toString();
//獲取密碼的值
String pass=upass.getText().toString();
//獲取網絡上的servlet路徑
String path="http://193.168.3.16:8080/Login/login.do";
//使用第三方
AsyncHttpClient ahc=new AsyncHttpClient();
//請求參數
RequestParams params=new RequestParams();
//給請求參數設鍵和值（鍵的名字和web后台保持一致）
params.put("name",name);
params.put("pass",pass);
//設值提交方式
ahc.post(this,path,params,new TextHttpResponseHandler(){
@Override
public void onFailure(int statusCode, Header[] headers, String responseBody, Throwable error) {
super.onFailure(statusCode, headers, responseBody, error);
}
@Override
public void onSuccess(int statusCode, Header[] headers, String responseBody) {
super.onSuccess(statusCode, headers, responseBody);
//吐司Android studio與web后台數據交互獲得的值
Toast.makeText(Main3Activity.this, responseBody, Toast.LENGTH_SHORT).show();
}
});
// @Override
// public void onSuccess(int statusCode, Header[] headers, String responseBody) {
// super.onSuccess(statusCode, headers, responseBody);
// Toast.makeText(MainActivity.this, responseBody, Toast.LENGTH_SHORT).show();
// }
// });
}
}