注意点：
1.Get和post这两种提交方式有何不同？
很明显post方式提交多了content-length和content-type这两项，所以post提交是要为这两项设置setRequestProperty属性
处理乱码问题
①客户端发送请求时没有对URL进行编码，我们只要使用URLEncoder.encode（keyValue,"UTF-8"）处理即可。
②Tomcat服务器在获取参数时，默认编码不是"UTF-8"，一般是"ISO-8859-1"，此时要如何处理呢？
主要思路是这样的：先把以"ISO-8859-1"(假设是这种编码，如果不是也无所谓)编码获取的数据转为最原始的二进码数据，然后再对该二进制数据以"UTF-8"格式进行重新编码
1.在一个web项目中创建一个servlet。让android项目访问servlet的路径，返回结果
loginServlet.java
package cn.com.servlet;
import java.io.IOException;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//服务器接受统一编码iso-8859-1,然后获取字符串时转化为utf-8
String name = new String(request.getParameter("name").getBytes("iso-8859-1"),"utf-8");
String password = request.getParameter("password");
System.out.println("name:"+name);
System.out.println("password:"+password);
if(name.equals("张三")&&password.equals("123")){
//往浏览器写字符串
response.getOutputStream().write("get方式登录成功".getBytes("utf-8")); //写到浏览器的编码是utf-8
}
else{
response.getOutputStream().write("get方式登录失败".getBytes("utf-8")); //写到浏览器的编码是utf-8
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//doGet(request, response);
//服务器接受统一编码iso-8859-1,然后获取字符串时转化为utf-8
String name = new String(request.getParameter("name").getBytes("iso-8859-1"),"utf-8");
String password = request.getParameter("password");
System.out.println("name:"+name);
System.out.println("password:"+password);
if(name.equals("张三")&&password.equals("123")){
//往浏览器写字符串
response.getOutputStream().write("post方式登录成功".getBytes("utf-8")); //写到浏览器的编码是utf-8
}
else{
response.getOutputStream().write("post方式登录失败".getBytes("utf-8")); //写到浏览器的编码是utf-8
}
}
}
2.android项目
（1）添加网络访问权限
<uses-permission android:name="android.permission.INTERNET"/>
（2）布局文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<EditText
android:id="@+id/name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="输入用户名"
android:text="张三"
/>
<EditText
android:id="@+id/password"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="输入密码" />
<Button
android:id="@+id/button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="get提交"
android:onClick="onClick1"
/>
<Button
android:id="@+id/button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="post提交"
android:onClick="onClick2"
/>
</LinearLayout>
MainActivity.java
package com.example.get;
import java.io.UnsupportedEncodingException;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
private EditText name,password;
private final int SUCCESS=1;
private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
if(msg.what==SUCCESS){
String result = (String) msg.obj;
if(result!=null){
Toast.makeText(MainActivity.this, result, 1).show();
}else{
Toast.makeText(MainActivity.this, "登陆失败", 1).show();
}
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
name = (EditText) findViewById(R.id.name);
password = (EditText) findViewById(R.id.password);
}
/**
* get方式提交
* @param view
*/
public void onClick1(View view){
final String loginName = name.getText().toString();
final String loginPasswor = password.getText().toString();
new Thread(){
@Override
public void run() {
String result = null;
try {
result = LoginService.loginByGet(loginName, loginPasswor);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Message msg = new Message();
msg.what=SUCCESS;
msg.obj=result;
handler.sendMessage(msg);
}
}.start();
}
/**
* post方式提交
* @param view
*/
public void onClick2(View view){
final String loginName = name.getText().toString();
final String loginPasswor = password.getText().toString();
new Thread(){
@Override
public void run() {
final String result=LoginService.loginByPost(loginName, loginPasswor);
if(result!=null){
//在主线程上运行
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, result, 1).show();
}
});
}
}
}.start();
}
}
3.业务类
LoginService .java
package com.example.get;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
public class LoginService {
public static String loginByGet(String name,String password) throws UnsupportedEncodingException{
//拼路径
String getpath = "http://10.162.0.171:8080/WebGet/LoginServlet?name="+URLEncoder.encode(name,"utf-8")+"&password="+URLEncoder.encode(password,"utf-8");//提交是得utf-8
String result = null;
int code;
try {
URL url = new URL(getpath);
//根据url发送http请求
HttpURLConnection conn=(HttpURLConnection) url.openConnection();
//发送提交方式
conn.setRequestMethod("GET");
//设置连接时间
conn.setConnectTimeout(5000);
//获取服务器返回码
code = conn.getResponseCode();
if(code==200){
InputStream is = conn.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len=0;
if((len=is.read(buffer))!=-1){
baos.write(buffer, 0, len);
}
is.close();
baos.close();
byte[] b=baos.toByteArray();
String s = new String(b);
result=s;
}else{
System.out.println(code);
result="";
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
result="";
}
return result;
}
public static String loginByPost(String name,String password){
String postpath = "http://10.162.0.171:8080/WebGet/LoginServlet";
String result = null;
int code;
try {
URL url = new URL(postpath);
HttpURLConnection conn=(HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setConnectTimeout(5000);
//name="+name+"&password="+password
//准备数据
String data ="name="+URLEncoder.encode(name, "utf-8")+"&password="+URLEncoder.encode(password, "utf-8");//提交是得utf-8
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty("Content-Length", data.length()+"");
//post 方式实际上是浏览器把数据写个服务器
conn.setDoOutput(true);//true 可以写出数据
OutputStream os=conn.getOutputStream();
os.write(data.getBytes());
code = conn.getResponseCode();
if(code==200){
InputStream is = conn.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len=0;
if((len=is.read(buffer))!=-1){
baos.write(buffer, 0, len);
}
is.close();
baos.close();
byte[] b=baos.toByteArray();
String s = new String(b);
result=s;
}else{
System.out.println(code);
result="";
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
result="";
}
return result;
}
}
