让你的APP和你的服务器畅快通讯

做安卓开发有很多时候都是要和web交互的，我们很难制作本地应用，这次把小弟整出来的安卓和服务器通讯贡献出来，希望能帮到需要的朋友，同时也是加深印象。

我们先来搭建安卓客户端，首先写好布局文件：

1.布局文件Register.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/fuction_fond_bg"
    android:orientation="vertical" >

    <ImageView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:src="@drawable/setting_btn" >
    </ImageView>

    <ScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:orientation="vertical" >

            <TextView
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:text="请输入您的注册信息："
                android:textColor="#6495ED"
                android:textSize="20dip" >
            </TextView>

            <View
                android:layout_width="fill_parent"
                android:layout_height="2dip"
                android:background="#FF909090" />

            <LinearLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_margin="20dip"
                android:background="#FFFFFF"
                android:orientation="vertical"
                android:padding="10dp" >

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal" >

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="帐　　 号:  "
                        android:textColor="#6495ED" >
                    </TextView>

                    <EditText
                        android:id="@+id/username"
                        android:layout_width="190dip"
                        android:layout_height="wrap_content" >
                    </EditText>
                </LinearLayout>

                <View
                    android:layout_width="fill_parent"
                    android:layout_height="2dip"
                    android:background="#FF909090" />

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal" >

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="密　　 码:  "
                        android:textColor="#6495ED" >
                    </TextView>

                    <EditText
                        android:id="@+id/password"
                        android:layout_width="190dip"
                        android:layout_height="wrap_content"
                        android:password="true" >
                    </EditText>
                </LinearLayout>

                <View
                    android:layout_width="fill_parent"
                    android:layout_height="2dip"
                    android:background="#FF909090" />

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal" >

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="确认密码 :  "
                        android:textColor="#6495ED" >
                    </TextView>

                    <EditText
                        android:id="@+id/confirmpsw"
                        android:layout_width="190dip"
                        android:layout_height="wrap_content"
                        android:password="true" >
                    </EditText>
                </LinearLayout>

                <View
                    android:layout_width="fill_parent"
                    android:layout_height="2dip"
                    android:background="#FF909090" />

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal" >

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="昵　　 称:  "
                        android:textColor="#6495ED" >
                    </TextView>

                    <EditText
                        android:id="@+id/nikename"
                        android:layout_width="190dip"
                        android:layout_height="wrap_content" >
                    </EditText>
                </LinearLayout>

                <View
                    android:layout_width="fill_parent"
                    android:layout_height="2dip"
                    android:background="#FF909090" />

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal" >

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="5dp"
                        android:text="性　　 别:  "
                        android:textColor="#6495ED" >
                    </TextView>

                    <RadioGroup
                        android:id="@+id/gender_group_rb"
                        android:layout_width="fill_parent"
                        android:layout_height="wrap_content"
                        android:orientation="horizontal" >

                        <RadioButton
                            android:id="@+id/male_rb"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:text="男　"
                            android:textColor="#6495ED" >
                        </RadioButton>

                        <RadioButton
                            android:id="@+id/female_rb"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:text="女"
                            android:textColor="#6495ED" >
                        </RadioButton>
                    </RadioGroup>
                </LinearLayout>

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal" >

                    <ImageView
                        android:layout_width="fill_parent"
                        android:layout_height="wrap_content" >
                    </ImageView>
                </LinearLayout>

                <View
                    android:layout_width="fill_parent"
                    android:layout_height="2dip"
                    android:background="#FF909090" />

                <Button
                    android:id="@+id/register_btn"
                    android:layout_width="fill_parent"
                    android:layout_height="40dp"
                    android:layout_margin="10dp"
                    android:background="@drawable/new_button_bg"
                    android:gravity="center"
                    android:text="注　册" />
            </LinearLayout>
        </LinearLayout>
    </ScrollView>

</LinearLayout>

 2.Activity文件：RegisterActivity.java

为了让大家看得方便，我逐个为大家讲解：

1.初始化视图控件：

/**
     * 初始化视图控件
     */
    private void initView() {
        username_et = (EditText) findViewById(R.id.username);
        password_et = (EditText) findViewById(R.id.password);
        confirmpsw_et = (EditText) findViewById(R.id.confirmpsw);
        nikename_et = (EditText) findViewById(R.id.nikename);
        register_btn = (Button) findViewById(R.id.register_btn);
        register_btn.setOnClickListener(listener);
        gender_group_rb = (RadioGroup) findViewById(R.id.gender_group_rb);
        gender_group_rb.setOnCheckedChangeListener(checkListener);
    }

 2.当我们填写好数据后，点击注册按钮，调用注册这个方法：

/**
     * 注册按钮的点击
     */
    private OnClickListener listener = new OnClickListener() {
        @Override
        public void onClick(View v) {
            doRegister();
        }
    };

    /**
     * 开始注册
     */
    private void doRegister() {
        pd = ProgressDialog.show(RegisterActivity.this, "正在注册..",
                "正在注册中..请稍后....", true, true);
        // 1.获取数据
        username = username_et.getText().toString();
        password = password_et.getText().toString();
        confirmpsw = confirmpsw_et.getText().toString();
        nickname = nikename_et.getText().toString();
        // 2.进行校验,不对返回，否则继续
        if (checkNull(username) || checkNull(password) || checkNull(confirmpsw)
                || checkNull(gender) || checkNull(nickname)) {
            Toast.makeText(this, "请填写完整数据", Toast.LENGTH_SHORT).show();
            // TODO 这里本应该完整校验的，暂时偷懒
            return;
        }
        // 3.开始向服务器注册
        Thread thread = new Thread(registerRunnable);
        thread.start();

    }

 因为做的比较简陋，详细的表单校验没有写，点击注册开启一个子线程来处理和服务器打交道的耗时操作。在注册的过程中用的httpUrlConnection连接服务器，向服务器提交注册信息。

/**
     * 开始注册的线程
     */
    Runnable registerRunnable = new Runnable() {
        @Override
        public void run() {
            // 1.拼装数据
            StringBuilder sb = new StringBuilder();
            sb.append("<users>");
            sb.append("<user>");
            sb.append("<username>");
            sb.append(username);
            sb.append("</username>");

            sb.append("<password>");
            sb.append(password);
            sb.append("</password>");

            sb.append("<nickname>");
            sb.append(nickname);
            sb.append("</nickname>");

            sb.append("<gender>");
            sb.append(gender);
            sb.append("</gender>");

            sb.append("</user>");
            sb.append("</users>");
            // 2.开始写数据
            byte content[] = sb.toString().getBytes();
            try {
                URL url = new URL(Constant.REGISTER_SERVLET);
                HttpURLConnection conn = (HttpURLConnection) url
                        .openConnection();
                conn.setDoInput(true);
                conn.setDoOutput(true);
                conn.setRequestMethod("POST");
                conn.setRequestProperty("Content-Type", "mutipart/form-data");
                conn.setRequestProperty("Content-Length", content.length + "");
                conn.getOutputStream().write(content);
                // 3.获取服务器返回的数据
                if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                    InputStream in = conn.getInputStream();

                    RegisterResultTool resultTool = new RegisterResultTool();
                    String result = resultTool.getResultFromInputStream(in);
                    // 4.提交结果
                    Message msg = new Message();
                    msg.obj = result;
                    msg.what = 200;
                    registerResultHandler.sendMessage(msg);

                }
            } catch (IOException e) {
                Message msg = new Message();
                msg.what = 400;
                registerResultHandler.sendMessage(msg);
                e.printStackTrace();
            }

            pd.cancel();
        }
    };

 向服务器提交数据后，服务器会返回一些结果数据，我们就需要处理这些结果数据：

/**
     * 处理服务器返回结果的类
     *
     * @author Larson
     *
     */
    private class RegisterResultTool {
        /**
         * 从服务器返回的数据中读取返回结果
         *
         * @param in
         * @return
         */
        public String getResultFromInputStream(InputStream in) {
            String result = "";
            SAXParserFactory sf = SAXParserFactory.newInstance();

            try {
                XMLReader xr = sf.newSAXParser().getXMLReader();

                RegisterResultHandler rrh = new RegisterResultHandler();
                xr.setContentHandler(rrh);
                xr.parse(new InputSource(in));
                result = rrh.getResult();

            } catch (Exception e) {
                e.printStackTrace();
            }
            return result;
        }

    }

    /**
     * 因为服务器返回的是xml形式，所以需要解析
     *
     * @author Larson
     *
     */
    private class RegisterResultHandler extends DefaultHandler {
        /**
         * 获得的服务器返回结果
         */
        private String result;
        /**
         * 临时存取数据的变量
         */
        private String var="";

        /**
         * 获取返回值
         *
         * @return
         */
        public String getResult() {
            return result;
        }

        @Override
        public void startElement(String uri, String localName, String qName,
                Attributes attributes) throws SAXException {
            super.startElement(uri, localName, qName, attributes);
        }

        @Override
        public void characters(char[] ch, int start, int length)
                throws SAXException {
            var += new String(ch, start, length);
            super.characters(ch, start, length);
        }

        @Override
        public void endElement(String uri, String localName, String qName)
                throws SAXException {
            /**
             * 取出info标签的数据（服务器返回的注册结果）
             */
            if (qName.equals("info")) {
                result = var.trim();
            }
            super.endElement(uri, localName, qName);
        }
    }

 获取结果后，在handler中刷新ui通知用户：

/**
 * 处理返回结果的handler
 * 如果返回的数据是服务器给的成功数据，注册成功，否则就是服务器有问题
 */
private Handler registerResultHandler = new Handler() {
    public void handleMessage(Message msg) {
        System.out.println(msg.obj+"-------------"+msg.what);
        switch (msg.what) {
        case 400:
            Toast.makeText(RegisterActivity.this, "注册失败.", Toast.LENGTH_SHORT).show();
            break;
        case 200:
            String str = (String) msg.obj;
            if(str.contains("regist_ok"))
                Toast.makeText(RegisterActivity.this, "注册成功.", Toast.LENGTH_SHORT).show();
            else
                Toast.makeText(RegisterActivity.this, "服务器未开放.", Toast.LENGTH_SHORT).show();
            break;
        default:
            break;
        }
    };
};

 接下来我们来写服务器端：

服务器段用registerServlet处理客户端请求：registerServlet.java:

package com.larson.pm;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.larson.tools.RegisterResultTool;

public class RegisterServlet extends HttpServlet {


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //1.获取输入输出流
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        InputStream in = request.getInputStream();
        //2.处理客户端发送的数据
        RegisterResultTool tool = new RegisterResultTool();
        String result = tool.register(in);

        //3.向客户端写相应数据
        out.write(result);
        out.flush();
        out.close();
        in.close();
    }


}

 servlet拿到客户端的数据inputStream，用一个工具类RegisterResultTool.java处理这些数据：

package com.larson.tools;

import java.io.InputStream;

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import com.larson.bean.UserInfo;
import com.larson.daoimpl.UserDao;
import com.larson.handler.RegisterHandler;

/**
 * 处理客户端发送过来数据的类
 *
 * @author Larson
 *
 */
public class RegisterResultTool {

    /**
     * 处理客户端发送过来数据的类
     * @param in
     *            客户端的流
     * @return 处理结果
     */
    public String register(InputStream in) {
        String result = null;
        StringBuilder sb = new StringBuilder();
        //1.获取解析工厂
        SAXParserFactory factory = SAXParserFactory.newInstance();
        XMLReader reader= null;
        try {
            //2.自定义解析过程
            reader = factory.newSAXParser().getXMLReader();
            RegisterHandler handler = new RegisterHandler();
            reader.setContentHandler(handler);

            //3.开始解析客户端过来的输入流,并把数据封装到userInfo的bean中
            reader.parse(new InputSource(in));
            UserInfo user = handler.getUser();

            //4.往服务器的数据库添加一条用户信息
            UserDao dao = new UserDao();
            dao.add(user);

            //5.完成后给客户端反馈消息
            sb.append("<info>");
            sb.append("regist_ok");
            sb.append("</info>");
        } catch (Exception e) {
            //TODO 解析失败
            sb.append("<info>");
            sb.append("regist_fail");
            sb.append("</info>");
            e.printStackTrace();
        }
        result = sb.toString();
        return result;
    }

}

 再次过程中，我们需要自定义一个sax解析xml的handler对数据进行处理封装到bean文件中：

RegisterHandler.java:

package com.larson.handler;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import com.larson.bean.UserInfo;

public class RegisterHandler extends DefaultHandler {
    private UserInfo user;
    private String var="";


    @Override
    public void startElement(String uri, String localName, String qName,
            Attributes attributes) throws SAXException {
        //遇到user标签就表示是一个user对象
        if(qName.equals("user"))
            user = new UserInfo();
        super.startElement(uri, localName, qName, attributes);
    }

    @Override
    public void endElement(String uri, String localName, String qName)
            throws SAXException {
        if("username".equals(qName))
            user.setUsername(var);
        if("password".equals(qName))
            user.setPassword(var);
        if("nickname".equals(qName))
            user.setNickname(var);
        if("gender".equals(qName))
            user.setGender(var);

        //设置完临时属性置空
        var="";
        super.endElement(uri, localName, qName);
    }

    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        var+=new String(ch, start, length);
        super.characters(ch, start, length);
    }

    /**
     * 获取填充完属性的user对象
     * @return
     */
    public UserInfo getUser() {
        return user;
    }

}

 ，处理完毕以后，需要把这些数据写入到数据库，生成一条新的用户信息记录，因此需要些一个UserDao。，而我们习惯性用jdbcutils管理连接，这里为了代码可重用更好，我把所有修改的方法集合到一个update方法里面：JdbcUtils.java：

package com.larson.tools;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import com.larson.handler.ResultSetHandler;

/**
 * 数据库相关
 * @author Larson
 *
 */
public class JdbcUtils {

//    private static ComboPooledDataSource ds = null;
    private static Connection conn;

    static{
        try{
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties");
            Properties properties = new Properties();
            properties.load(in);
            String url = properties.getProperty("url");
            String user = properties.getProperty("user");
            String passwd  = properties.getProperty("password");
            String driver =  properties.getProperty("driver");


            Class.forName(driver);
            conn = DriverManager.getConnection(url, user, passwd);


//          ds = new ComboPooledDataSource();
//          ds.setDriverClass(driver);
//          ds.setJdbcUrl(url);
//          ds.setUser(user);
//          ds.setPassword(passwd);
//
//          ds.setInitialPoolSize(10);
//          ds.setMinPoolSize(5);
//          ds.setMaxPoolSize(20);
//
//          ds = new ComboPooledDataSource();

        }catch (Exception e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    /**
     * 获取连接
     * @return
     * @throws SQLException
     */
    public static Connection getConnection() throws SQLException{
//      return ds.getConnection();
        return conn;
    }

    /**
     * 释放连接
     * @param conn
     * @param st
     * @param rs
     */
    public static void release(Connection conn,Statement st,ResultSet rs){

        if(rs!=null){
            try{
                rs.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
            rs = null;

        }
        if(st!=null){
            try{
                st.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
        }
        if(conn!=null){
            try{
                conn.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
        }
    }


    /**
     * 替换dao中的增删改方法
     * @param sql
     * @param params
     * @throws SQLException
     */
    public static void update(String sql,Object params[]) throws SQLException{
        Connection conn = null;
        PreparedStatement st = null;
        ResultSet rs = null;

        try{
            conn = getConnection();
            st = conn.prepareStatement(sql);
            for(int i=0;i<params.length;i++){
                st.setObject(i+1, params[i]);
            }
            st.executeUpdate();

        }finally{
            release(conn, st, rs);
        }
    }

    /**
     * 替换所有dao中的查询   策略模式
     * @param sql
     * @param params
     * @param rsh
     * @return
     * @throws SQLException
     */
    public static Object query(String sql,Object params[],ResultSetHandler rsh) throws SQLException{

        Connection conn = null;
        PreparedStatement st = null;
        ResultSet rs = null;

        try{
            conn = getConnection();
            st = conn.prepareStatement(sql);
            for(int i=0;i<params.length;i++){
                st.setObject(i+1, params[i]);
            }
            rs = st.executeQuery();
            return rsh.handler(rs);

        }finally{
            release(conn, st, rs);
        }
    }
}

 然后便是UserDao.java：

package com.larson.daoimpl;

import com.larson.bean.UserInfo;
import com.larson.exception.DaoException;
import com.larson.handler.BeanHandler;
import com.larson.tools.JdbcUtils;

public class UserDao {

    public void add(UserInfo user) {
        try {
            String sql = "insert into user(username,password,gender,nickname) values(?,?,?,?)";
            Object params[] = {  user.getUsername(),
                    user.getPassword(), user.getGender(),user.getNickname() };

for(Object obj:params)
    System.out.println("userdao add---"+obj);

            JdbcUtils.update(sql, params);
        } catch (Exception e) {
            throw new DaoException(e);
        }
    }

    public void update(UserInfo user) {
        try {
            String sql = "update user set user=?,password=?,gender=?,nickname=? where id=?";
            Object params[] = { user.getId(), user.getUsername(),
                    user.getPassword(), user.getNickname(), user.getId() };
            JdbcUtils.update(sql, params);
        } catch (Exception e) {
            throw new DaoException(e);
        }
    }

    public void delete(String id) {
        try {
            String sql = "delete from user where id=?";
            Object params[] = { id };
            JdbcUtils.update(sql, params);
        } catch (Exception e) {
            throw new DaoException(e);
        }
    }

    public UserInfo find(String id) {
        try {
            String sql = "select * from user where id=?";
            Object params[] = { id };
            return (UserInfo) JdbcUtils.query(sql, params, new BeanHandler(
                    UserInfo.class));
        } catch (Exception e) {
            throw new DaoException(e);
        }
    }

}

 为了方便，我把bean文件也贴出来：

userInfo.java:

package com.larson.bean;

public class UserInfo {
    private int id;
    private String username;
    private String password;
    private String gender;
    private String nickname;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

}

 本来准备用数据库连接池的，可是老是报错，就是上面注释的那几行，有懂的人麻烦告诉我，感激不尽。