我使用Java开发了一个REST API,实现了Jersey
。现在我正在尝试连接我的Android应用程序。
下面的代码与我的REST API有关。
PatientJSONService
import bean.PatientBean;
import bean.UserBean;
import db.PatientImpl;
import db.PatientInterface;
import db.UserImpl;
import db.UserInterface;
import java.util.List;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
@Path("/patient")
public class PatientJSONService
{
@POST
@Path("/insertPatient")
@Consumes(MediaType.APPLICATION_JSON)
public String insertPatient(PatientBean bean)
{
System.out.println("Printed");
PatientInterface patientInterface = new PatientImpl();
String insertUser = patientInterface.insertPatient(bean);
return insertUser;
}
@GET
@Path("/getAllPatients")
@Produces(MediaType.APPLICATION_JSON)
public List<PatientBean> getAllPatients()
{
PatientInterface patinetInterface=new PatientImpl();
List<PatientBean> allPatients = patinetInterface.getAllPatients();
return allPatients;
}
@POST
@Path("/getPatientById/{id}")
@Produces(MediaType.APPLICATION_JSON)
public PatientBean getPatientByFlareId(@PathParam("id")String flareId)
{
PatientInterface patinetInterface=new PatientImpl();
PatientBean patientById = patinetInterface.getPatientById(id);
return patientById;
}
}
PatientBean
public class PatientBean {
private int idPatient;
private String id;
public int getIdPatient() {
return idPatient;
}
public void setIdPatient(int idPatient) {
this.idPatient = idPatient;
}
public String getID() {
return flareID;
}
public void setID(String id) {
this.id = id;
}
}
PatientImpl - (数据库类)
public class PatientImpl implements PatientInterface {
@Override
public String insertPatient(PatientBean patientBean)
{
String sql = "INSERT INTO patient (id) values(?)";
String result="";
Connection con = null;
PreparedStatement ps = null;
try
{
con = DBMaster.getInstance().getConnection();
con.setAutoCommit(false);
ps = con.prepareStatement(sql.toLowerCase());
ps.setString(1,patientBean.getID());
ps.executeUpdate();
con.commit();
result = Common.SUCCESS;
}
catch(Exception e)
{
try
{
con.rollback();
e.printStackTrace();
result = Common.ROLLBACK;
}
catch (SQLException ex)
{
ex.printStackTrace();
result = Common.ROLLBACK_FAILED;
}
}
finally
{
try
{
ps.close();
con.close();
} catch (SQLException ex)
{
ex.printStackTrace();
}
}
System.out.println(result);
return result;
}
}
现在,您对REST API的外观有了清晰的认识。让我们看看我如何编程我的Android应用程序来访问此API。在这里,我实际上正在使用retrofit 2
- http://square.github.io/retrofit/
MainActivity
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import bean.Common;
import bean.PatientBean;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity {
public static final String URL = "http://x.x.x.x:8080/TestRest/rest/";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
restCall();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private void restCall()
{
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
YourEndpoints request = retrofit.create(YourEndpoints.class);
PatientBean patientBean= new PatientBean ();
patientBean.setId(SLKRT0065);
Call<ResponseBody> yourResult = request.insertPatient(patientBean);
yourResult.enqueue(new Callback<ResponseBody>() {
@Override
public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
try {
Log.d("MainActivity", "RESPONSE: " + response.body().string());
}
catch(Exception e)
{
e.printStackTrace();
}
}
@Override
public void onFailure(Call<ResponseBody> call, Throwable t) {
try {
t.printStackTrace();
Log.d("MainActivity", "RESPONSE: "+"FAILED");
}
catch(Exception e)
{
e.printStackTrace();
}
}
});
}
}
从上面的课程中,看一下发生REST调用的方法restCall()
。
YourEndpoints
public interface YourEndpoints {
@POST("patient/insertPatient")
Call<ResponseBody> insertPatient(@Body PatientBean patientBean);
}
我不知道我做错了什么,但它根本没有用。当我运行此代码时,我在此处NULLPOINTERException
得到一个Log.d("MainActivity", "RESPONSE: " + response.body().string());
,这意味着响应可能为null /如果我删除该部分代码运行正常,但我在数据库中看不到任何内容。
我该如何解决这个问题?