这是网址'http://localhost:8080/shopping/' 我只知道tomcat和MySQL已连接，并且服务器端没有错误
我认为该错误是由于android应用和tomcat服务器之间的连接代码
错误： this is the screenshot of errors
文本错误：
System.err：位于spoorthy.shopping.RegisterThread.run（RegisterThread.java:31）
java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法'Boolean java.lang.String.equals（java.lang.Object）'
System.err：在spoorthy.shopping.Register.register（Register.java:93）
System.err：在spoorthy.shopping.Register $ 1.onClick（Register.java:28）
这是Android中ServerURL.java文件的内容
package spoorthy.shopping;
public class ServerURL {
static String url;
public static void setURL(String u){
url = "http://"+u+":8080/shopping/";
}
public static String getURL(){
return url;
}
}
这是MainActivity.java文件的内容
package spoorthy.shopping;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
EditText ip;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initClickListner();
}
private void initClickListner() {
ip = (EditText)findViewById(R.id.ip);
Button admin = (Button) findViewById(R.id.login);
admin.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
String s1 = ip.getText().toString().trim();
ServerURL.setURL(s1);
Intent intent = new Intent(MainActivity.this, Login.class);
startActivity(intent);
}
});
Button customer = (Button) findViewById(R.id.register);
customer.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
String s1 = ip.getText().toString().trim();
ServerURL.setURL(s1);
Intent intent = new Intent(MainActivity.this, Register.class);
startActivity(intent);
}
});
}
}
这是register.java文件的内容
package spoorthy.shopping;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class Register extends Activity {
EditText user,pass,place,email,contact;
Button signup;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
user = (EditText) findViewById(R.id.username);
pass = (EditText) findViewById(R.id.password);
place = (EditText) findViewById(R.id.address);
email = (EditText) findViewById(R.id.mail);
contact = (EditText) findViewById(R.id.contact);
signup=(Button) findViewById(R.id.signup);
signup.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
try{
register();
}catch(Exception e){
Toast.makeText(Register.this, e.getMessage(), Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
});
}
public void register(){
//read values from fields
String s1 = user.getText().toString();
String s2 = pass.getText().toString();
String s3 = place.getText().toString();
String s4 = email.getText().toString();
String s5 = contact.getText().toString();
//sb.append("1of"+list.size());
//check values should not be empty
if(s1.trim().length() == 0 ||s1 == null){
Toast.makeText(Register.this, "Please enter username", Toast.LENGTH_LONG).show();
user.requestFocus();
return;
}
if(s2.trim().length() == 0 ||s2 == null){
Toast.makeText(Register.this, "Please enter password", Toast.LENGTH_LONG).show();
pass.requestFocus();
return;
}
if(s3.trim().length() == 0 ||s3 == null){
Toast.makeText(Register.this, "Please enter address", Toast.LENGTH_LONG).show();
place.requestFocus();
return;
}
if(s4.trim().length() == 0 ||s4 == null){
Toast.makeText(Register.this, "Please enter emailid", Toast.LENGTH_LONG).show();
email.requestFocus();
return;
}
if(!CheckMail.checkMail(s4)){
Toast.makeText(Register.this, "Please enter valid email id", Toast.LENGTH_LONG).show();
email.requestFocus();
return;
}
if(s5.trim().length() == 0 || s5 == null){
Toast.makeText(Register.this, "Please enter contact no", Toast.LENGTH_LONG).show();
contact.requestFocus();
return;
}
StringBuilder request = new StringBuilder();
request.append("t1="+s1+"&t2="+s2+"&t3="+s3+"&t4="+s4+"&t5="+s5);
//progress dialog
ProgressDialog dialog = new ProgressDialog(Register.this);
dialog.setMessage("Processing...");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
dialog.show();
//call thread
RegisterThread register = new RegisterThread(request.toString());
try{
//wait till thread complete its execution
register.join();
dialog.dismiss();
//get response from server
String res = register.getResponse();
//if response successfull then go to LoginActivity
if (res.equals("success")) {
Intent in1 = new Intent(Register.this,Login.class);
startActivity(in1);
} else {
//show login fail
Toast.makeText(Register.this, "failed to register", Toast.LENGTH_LONG).show();
}
} catch (Exception e) {
Toast.makeText(Register.this, e.getMessage(), Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
public void printError(String msg){
user.setText(msg);
Toast.makeText(Register.this, msg, Toast.LENGTH_LONG).show();
}
}
这是我的RegisterThread.java文件的内容
package spoorthy.shopping;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
public class RegisterThread extends Thread{
//query variable
String request;
//response from server
String response;
//return server response
public String getResponse(){
return response;
}
//assign query here. This query contains all registration values
public RegisterThread(String request){
this.request = request;
//call to run
start();
}
//start network connection
public void run(){
try{
URL url = new URL(ServerURL.getURL()+"Register");
URLConnection con = url.openConnection();
con.setDoOutput(true);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(con.getOutputStream()));
bw.write(request);
bw.flush();
BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));
response = br.readLine();
}catch(Exception e){
//register.printError(e.getMessage());
e.printStackTrace();
}
}
}