android 增删查完整例子

       这个Android增删查的例子本来不打算写的，不过觉得这个热门的技术，不写一下，就跟不上潮流，另外也是太多人写了几乎雷同，似乎也没什么好些的，不过看到网上比较难找到完整的前后台进行通讯交互的例子，就写一下；

      本例子涉及的面不算广，不过涉及的知识对于初学者来说也不少，具体涉及到java，servlet，mysl数据库连接，sql语句，json等，对于初学者来说，应该是不错的入门案例，如果有时间的人，可以对这个进行重构，扩展

   现在先来看一下一个简单的网站架构图：

 

 

这里实现的是android部分

  首先，表结构：

    

CREATE TABLE  androiduser` (
  `name` varchar(45) NOT NULL default '',
  `age` int(10) unsigned NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 主要的android类：

 

   

package minn.minnapp;


/**
 * 
 * @author minn
 * @@@ 394286006
 * @email [e-mail]
 * 
 */
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@SuppressLint("NewApi")
public class MainActivity extends Activity {

	private View user = null;
	private UserService userService = null;
	private final static String HTTP_STR = "http://192.168.3.100:8080/minnAndroidServer/userServlet";

	@TargetApi(Build.VERSION_CODES.GINGERBREAD)
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
				.detectDiskReads().detectDiskWrites().detectNetwork()
				.penaltyLog().build());
		StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
				.detectLeakedSqlLiteObjects().detectLeakedClosableObjects()
				.penaltyLog().penaltyDeath().build());

		userService = new UserService();
		initBtn();
		search();
	}

	private void createWin() {
		LayoutInflater layoutInflater = LayoutInflater.from(this);
		user = layoutInflater.inflate(R.layout.user, null);

		new AlertDialog.Builder(this).setTitle(R.string.title_add)
				.setView(user)
				.setPositiveButton("确定", new DialogInterface.OnClickListener() {

					@Override
					public void onClick(DialogInterface dialog, int which) {
						add();
					}

				}).setNegativeButton("取消",

				new DialogInterface.OnClickListener() {

					@Override
					public void onClick(DialogInterface dialog, int which) {

					}

				}).show();
	}

	private void initBtn() {
		((Button) findViewById(R.id.add))
				.setOnClickListener(new OnClickListener() {

					@Override
					public void onClick(View v) {
						createWin();
					}

				});

		((Button) findViewById(R.id.close))
				.setOnClickListener(new OnClickListener() {

					@Override
					public void onClick(View v) {
						// TODO Auto-generated method stub
						exit();
					}
				});

		((Button) findViewById(R.id.search_btn))
				.setOnClickListener(new OnClickListener() {

					@Override
					public void onClick(View v) {
						// TODO Auto-generated method stub
						search();
					}
				});
	}

	private void exit() {
		this.finish();
		System.exit(0);
	}

	private void add() {
		Log.i("add", "开始新增数据");
		EditText name = ((EditText) user.findViewById(R.id.name));
		EditText age = ((EditText) user.findViewById(R.id.age));
		StringBuffer params = new StringBuffer();
		params.append("?method=add");
		try {
			params.append("&name="
					+ URLEncoder.encode(name.getText().toString(), "UTF-8"));
			params.append("&age=" + age.getText().toString());
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		userService.request(HTTP_STR + params.toString());
		search();
	}

	private void del(String name, String age) {
		Log.i("del", "开始删除数据");
		StringBuffer params = new StringBuffer();
		params.append("?method=del");
		try {
			params.append("&name=" + URLEncoder.encode(name, "UTF-8"));
			params.append("&age=" + age);
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		userService.request(HTTP_STR + params.toString());

		search();
	}

	private void search() {
		Log.i("search", "开始加载数据");
		StringBuffer params = new StringBuffer();
		params.append("?method=search");
		try {
			EditText name = ((EditText) findViewById(R.id.search_name));
			String sname = "";
			if (name.getText() != null)
				sname = name.getText().toString();
			params.append("&name=" + URLEncoder.encode(sname, "UTF-8"));
			JSONObject jobj = userService.request(HTTP_STR + params.toString());
			JSONArray jarr = (JSONArray) jobj.get("data");

			TableLayout table = (TableLayout) findViewById(R.id.vtable);
			table.removeViews(1, table.getChildCount() - 1);
			for (int i = 0; i < jarr.length(); i++) {
				final JSONObject obj = jarr.getJSONObject(i);
				TableRow row = new TableRow(this);
				TextView t = new TextView(this);
				t.setWidth(80);
				t.setGravity(Gravity.CENTER);
				t.setPadding(3, 3, 3, 3);
				t.setText(obj.getString("name"));
				row.addView(t);
				t = new TextView(this);
				t.setGravity(Gravity.CENTER);
				t.setPadding(5, 3, 3, 3);
				t.setText(obj.getString("age"));
				row.addView(t);
				Button b = new Button(this);
				b.setPadding(3, 3, 3, 3);
				b.setWidth(20);
				b.setText("删除");
				b.setOnClickListener(new OnClickListener() {

					@Override
					public void onClick(View v) {
						// TODO Auto-generated method stub

						try {
							del(obj.getString("name"), obj.getString("age"));
						} catch (JSONException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
					}

				});
				row.addView(b);

				table.addView(row, new TableLayout.LayoutParams());
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

 

 

 android发送请求公共方法：

/**
 * 
 * @author minn
 * @@@ 394286006
 * @email [e-mail]
 *
 */
public JSONObject request(String req) {
		JSONObject rsobj=null;
		try {
			HttpClient hc=new DefaultHttpClient();
			HttpGet hg=new HttpGet(req);
			HttpResponse response=hc.execute(hg);
			InputStreamReader isr=new InputStreamReader(response.getEntity().getContent());
		BufferedReader br=new BufferedReader(isr);
		String rs="";
		String rl=null;
		while((rl=br.readLine())!=null)
			rs+=rl;
		isr.close();
		
		rsobj=new JSONObject(rs);

		} catch (Exception e) {
			//e.printStackTrace();
		}
		return rsobj;
	}

 

 

 

j2ee工程主要代码：

 

package minn.service;

/**
 * @author minn
 * @QQ 394286006
 * @email [e-mail]
 * 
 */
public class UserService {

	DaoOperator daoOperator=new DaoOperator();
	
	public JSONObject search(String name) throws Exception{
		
		JSONObject jobj=new JSONObject();
		try {
			jobj.put("success", true);
			jobj.put("data", daoOperator.query("SELECT name,age FROM androiduser where name like '"+name+"%'"));
			
		} catch (JSONException e) {
			// TODO Auto-generated catch block
			jobj.put("success", false);
			e.printStackTrace();
		}
		
		return jobj;
	}
	
	public JSONObject add(String name ,String age) throws Exception{
		
		JSONObject jobj=new JSONObject();
		try {
			jobj.put("success", true);
			daoOperator.execute("insert into androiduser(name,age) values('"+name+"',"+age+")");
			
		} catch (JSONException e) {
			// TODO Auto-generated catch block
			jobj.put("success", false);
			e.printStackTrace();
		}
		
		return jobj;
	}
	
	
	public JSONObject del(String name,String age) throws Exception{
		
		JSONObject jobj=new JSONObject();
		try {
			jobj.put("success", true);
			daoOperator.execute("delete from androiduser where name='"+name+"' and age="+age);
			
			
		} catch (JSONException e) {
			// TODO Auto-generated catch block
			jobj.put("success", false);
			e.printStackTrace();
		}
		
		return jobj;
	}

}

 效果图: