Android 入门列子 （三） Android请求获取Java后端数据,登录界面

Android请求获取Java后端数据的例子

 

先上个登录界面图：   

 

主要实现：

java后端的代码 + Android的代码

1、java后端代码

（1）、先创个User类

package com.szerp.android.entity;

import net.sf.json.JSONObject;

public class User {
	private String userid;
	private String account;
    private String username;
    private String passwd;
    
    
    public User() {
    }
    
    public User(String userid, String account, String username, String passwd) {
        this.userid = userid;
        this.account = account;
        this.username = username;
        this.passwd = passwd;
    }
    
    public static User json2novel (JSONObject json) {
        try {
            return new User(json.getString("userid"),
                    json.getString("account"),
                    json.getString("username"),
                    json.getString("passwd")
            );
        }catch (Exception ex) {
        	ex.printStackTrace();
        }
        return null;
    }
    
    public String getUserid() {
		return userid;
	}

	public void setUserid(String userid) {
		this.userid = userid;
	}

	public String getAccount() {
		return account;
	}

	public void setAccount(String account) {
		this.account = account;
	}

	public String getUsername() {
		return username;
	}

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

	public String getPasswd() {
		return passwd;
	}

	public void setPasswd(String passwd) {
		this.passwd = passwd;
	}
    
}

 

（2）、建个LoginServlet（public class LoginServlet extends HttpServlet）

package com.szerp.android.service.impl;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

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

import org.jeecgframework.core.util.PasswordUtil;
import org.jeecgframework.web.system.pojo.base.TSBaseUser;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import com.szerp.android.entity.User;
import com.szerp.android.util.JDBCUtils;

import net.sf.json.JSONObject;
public class LoginServletImpl extends HttpServlet  {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	private JdbcTemplate jdbcTemplate = new JdbcTemplate(JDBCUtils.getDataSource());
	  
	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}
	
	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		 request.setCharacterEncoding("UTF-8");
		 response.setContentType("text/html;charset=UTF-8");
		
		 String username = request.getParameter("username").trim();
		 String passwd = request.getParameter("passwd").trim();
	     String password = PasswordUtil.encrypt(username, passwd, PasswordUtil.getStaticSalt());
	      //1获取JDBCTemplate 对象    
	     String hql = "SELECT * FROM  t_s_base_user u where u.userName = '"+username+"' and u.password = '"+password+"'";
	     List users = jdbcTemplate.query(hql, new BeanPropertyRowMapper<>(TSBaseUser.class));

	     JSONObject json = new JSONObject();
	     List list = new ArrayList<>();
	     if ((users != null) && (users.size() > 0)) {
	    	 TSBaseUser tsUser  = (TSBaseUser)users.get(0); 
	 		System.out.println("userName==="+username);
			System.out.println("passwd==="+passwd);			
			
			User user = new User();
			user.setUserid("1");
			user.setUsername(tsUser.getUserName());
			user.setPasswd(tsUser.getPassword());
			
			list.add(user);
			json.put("data", list);
			PrintWriter out = response.getWriter();
			out.write(json.toString());//返回json数据
	    	 
	     }else{
				json.put("data", list);
				PrintWriter out = response.getWriter();
				out.write(json.toString());//返回json数据
	     }

	}
	

	



}

（3）、建个跨域过滤器CorsFilter（public class CorsFilter implements Filter）

package com.szerp.android.controller;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class CorsFilter implements Filter {

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		HttpServletResponse res = (HttpServletResponse) response;
		res.setContentType("text/html;charset=UTF-8");
		res.setHeader("Access-Control-Allow-Origin", "*");//"*"所有域名可访问
		res.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
		res.setHeader("Access-Control-Max-Age", "0");
		res.setHeader("Access-Control-Allow-Headers", "Origin, No-Cache, X-Requested-With, If-Modified-Since, Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With,userId,token");
		res.setHeader("Access-Control-Allow-Credentials", "true");
		res.setHeader("XDomainRequestAllowed", "1");
		chain.doFilter(request, response);
	}

	@Override
	public void init(FilterConfig config) throws ServletException {

	}

	@Override
	public void destroy() {

	}

}

 

（4）、配置一下web.xml

 

	
	
		LoginServlet
		com.android.service.impl.LoginServletImpl
	
	
		LoginServlet
		/LoginServlet
	

  
    
	  
		cors  
		com.android.controller  
	  
	  
		cors  
		/*  
	

 

2、Android代码

（1）、写个登录界面 activity_login.xml

 

（2）、再写点LoginActivity代码

 

请求网络数据需要权限，在manifest添加权限：

 

 

这里使用了 AsyncHttpClient 来请求 java后端 的数据

要在build里添加：

compile 'com.loopj.android:android-async-http:1.4.9'

LoginActivity

package com.example.peiming.a01;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;

import org.json.JSONArray;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

import cz.msebera.android.httpclient.Header;
import entity.User;

public class LoginActivity extends AppCompatActivity implements View.OnClickListener {
    AsyncHttpClient client;//异步加载
    List ls_user = null;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);


        Button button = (Button) findViewById(R.id.login_btn);
        button.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.login_btn:
                EditText idText= (EditText)findViewById(R.id.login_id);
                EditText passwordText = (EditText) findViewById(R.id.login_password);
                String username = idText.getText().toString();
                String password = passwordText.getText().toString();

                client = new AsyncHttpClient();//实例化AsyncHttpClient
                //这里的IP(192.168.43.234:8080)要换成你自己电脑的IP ！！！
                String url = "http://192.168.2.199:8080/cmferp/LoginServlet?username=" + username + "&passwd=" + password;
                ls_user = new ArrayList<>();//初始化
                client.get(url, new AsyncHttpResponseHandler() {
                    @Override
                    public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
                        try {
                            JSONObject jsonObject = new JSONObject(new String(responseBody));
                            JSONArray jsonArray = jsonObject.getJSONArray("data");
                            for (int i=0; i= 3;
    }

    private boolean isPasswordValid(String password) {
        return  password.length() >= 6;
    }




}

 

（4）、建个User类

 

package entity;

import org.json.JSONException;
import org.json.JSONObject;

/**
 * Created by ZhouJie on 2017/9/28.
 */

public class User {
    private String userid;
    private String account;
    private String username;
    private String passwd;


    public User() {
    }

    public User(String userid, String account, String username, String passwd) {
        this.userid = userid;
        this.account = account;
        this.username = username;
        this.passwd = passwd;
    }

    public static User json2novel (JSONObject json) {
        try {
            return new User(json.getString("userid"),
                    json.getString("account"),
                    json.getString("username"),
                    json.getString("passwd")
            );
        }catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }

    public String getUserid() {
        return userid;
    }

    public void setUserid(String userid) {
        this.userid = userid;
    }

    public String getAccount() {
        return account;
    }

    public void setAccount(String account) {
        this.account = account;
    }

    public String getUsername() {
        return username;
    }

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

    public String getPasswd() {
        return passwd;
    }

    public void setPasswd(String passwd) {
        this.passwd = passwd;
    }
}

 

代码大概就这个样子了,以上都有参照例子都有按照自己的需求改动。参考例子代码 百度网盘

链接：https://pan.baidu.com/s/13p5YMFPSfabAxL1ZPLmPsg 
提取码：rgnp

 

友情例子 

https://blog.csdn.net/u012964281/article/details/40625967