import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.campus.book.R;
import com.campus.book.entity.User;
import com.campus.book.util.http.OKHttpUtil;
import com.google.gson.Gson;

public class LoginActivity extends AppCompatActivity {
//這個(gè)url可以通過(guò)cmd中輸入    ipconfig   IPv4 地址即為本地電腦的地址   8081為后端的端口號(hào)
    private String baseUrl="http://192.168.xxx.1:8081";
   
    private TextView tv=null;
    EditText userId = null;
    EditText pwd = null ;
    Button login=null;
    private Button registry=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        setTitle("登錄");
        tv=findViewById(R.id.tv);
        login = (Button)findViewById(R.id.login);
        registry = (Button)findViewById(R.id.registry);
        userId=(EditText) findViewById(R.id.userId);
        pwd=findViewById(R.id.pwd);
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                String id = userId.getText().toString();
                String password=pwd.getText().toString();
                User user=new User(id,password);
                Gson gson=new Gson();
                String json=gson.toJson(user);
                String args[]=new String[]{"user","login"};
                String res= OKHttpUtil.postSyncRequest(baseUrl,json,args);
                Log.d("同步:",res);
                res= OKHttpUtil.postAsyncRequest(baseUrl,json,args);
                Log.d("異步:",res);
            }
        });

        registry.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                String args[]=new String[]{"user","getUser","123"};
                String res= OKHttpUtil.getSyncRequest(baseUrl,args);
                System.out.println("同步："+res);

                String args1[]=new String[]{"user","getUser","123"};
                 res= OKHttpUtil.getAsyncRequest(baseUrl,args1);
                System.out.println("異步："+res);

            }
        });
    }
}

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activity.LoginActivity">
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/tv"
    android:text="內(nèi)容："/>
    <FrameLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <ImageView
            android:id="@+id/mainBg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/login" />
<!--@drawable/login改成相應(yīng)的背景圖-->
        <TableLayout
            android:layout_width="350dp"
            android:layout_height="match_parent"
            android:stretchColumns="*"
            android:layout_marginBottom="150sp"
            android:layout_gravity="center" >

            <TableRow android:layout_height="match_parent">
                <EditText
                    android:id="@+id/userId"
                    android:layout_column="0"
                    android:layout_span="2"
                    android:hint="請(qǐng)輸入手機(jī)號(hào)"
                    android:textColorHint="#FFFFFF"
                    android:textColor="#FFFFFF"
                    android:textCursorDrawable="@drawable/cursor_color"
                    android:textSize="15sp" />
            </TableRow>

            <TableRow android:layout_height="match_parent" >
                <EditText
                    android:id="@+id/pwd"
                    android:inputType="textPassword"
                    android:layout_column="0"
                    android:layout_span="2"
                    android:hint="請(qǐng)輸入密碼"
                    android:textColorHint="#FFFFFF"
                    android:textColor="#FFFFFF"
                    android:textCursorDrawable="@drawable/cursor_color"
                    android:textSize="15sp" />
            </TableRow>

            <TableRow android:layout_height="match_parent">
                <Button
                    android:id="@+id/login"
                    android:layout_height="wrap_content"
                    android:textColor="#FFFFFF"
                    android:background="#000000"
                    android:layout_margin="8dp"
                    android:textSize="15sp"
                    android:text="登錄" />
                <Button
                    android:id="@+id/registry"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#FFFFFF"
                    android:background="#000000"
                    android:layout_margin="8dp"
                    android:textSize="15sp"
                    android:text="注冊(cè)" />
            </TableRow>

        </TableLayout>

    </FrameLayout>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" >
    <size android:width="2dp" />
    <solid android:color="@android:color/black" />
</shape>

@RestController
@RequestMapping("http://user")
public class UserController {
	@Autowired
	private UserService userService;

	//Gson gson= JsonBean.getGson();
    static Gson gson=new GsonBuilder().serializeNulls().create();
	@GetMapping("/list")
	public List<User> list() {
		return this.userService.list();
	}

	@PostMapping("/login")
	public User login(String json){
		User result=null;
		User user=null;
		User user1=null;
		try{
			user=gson.fromJson(json,User.class);
		}catch (Exception e){
			e.printStackTrace();
		}
		user1=userService.getById(user.getUserId());
		if(user1!=null){//存在該賬戶(hù)
			if(user1.getPassword().equals(user.getPassword())){//密碼正確
				result=user1;
			}else{//密碼錯(cuò)誤

			}
		}else{//不存在該賬戶(hù)

		}
		return result;
	}

	@GetMapping("/getUser/{id}")
	public User getUser(@PathVariable("id") Serializable id){
		User user=userService.getById(id);
		if(user!=null){//存在

		}else{//不存在

		}
		return user;
	}
}