java.lang.String中不能转换到的JSONObjectlang、java、JSONObject、String
2023-09-08 09:16:38
作者：别拿你的牙签当大炮
我试图从数据库中检索数据时面临的问题：
错误解析数据org.json.JSONException：值＆LT; java.lang.String类型的DOCTYPE不能转换为JSONObject的！公共类AllProductsActivity扩展ListActivity { //进度对话框 私人ProgressDialog pDialog; //创建JSON解析器对象 JSONParser jParser =新JSONParser（）; ArrayList的＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;产品列表; // URL获得所有产品清单 私人静态字符串url_all_products =http://192.168.1.3/android_connect/get_all_products.php; // JSON节点名称 私有静态最后弦乐TAG_SUCCESS =成功; 私有静态最后弦乐TAG_PRODUCTS =产品; 私有静态最后弦乐TAG_PID =PID; 私有静态最后弦乐TAG_NAME =名; //产品JSONArray JSONArray产品= NULL; @覆盖 公共无效的onCreate（捆绑savedInstanceState）{ super.onCreate（savedInstanceState）; 的setContentView（R.layout.all_products）; //为哈希映射的ListView 产品列表=新的ArrayList＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;（）; //装载产品在后台线程 新LoadAllProducts（）执行（）; //获取列表视图 ListView控件LV = getListView（）; //在选课单品 //启动编辑产品屏幕 lv.setOnItemClickListener（新OnItemClickListener（）{ @覆盖 公共无效onItemClick（适配器视图＆LT;＆GT;母公司，观景， INT位置，长的id）{ //从选定的ListItem得到的值 字符串的pid =（（的TextView）view.findViewById（R.id.pid））的getText（）。 的ToString（）; //开始新意图 在意向=新意图（getApplicationContext（） EditProductActivity.class）; //发送到PID下一个活动 in.putExtra（TAG_PID，PID）; //开始新的活动，期待一些回响应 startActivityForResult（在100）; } }）; } //从编辑产品的活动响应 @覆盖 保护无效的onActivityResult（INT申请code，INT结果code，意图数据）{ super.onActivityResult（要求code，结果code，数据）; //如果结果code 100 如果（结果code == 100）{ //如果结果code 100接收 //意味着用户编辑/删除产品 //重新载入该画面 意向意图= getIntent（）; 完（）; startActivity（意向）; } } / ** *背景异步任务以通过HTTP请求负载的所有产品 * * / 类LoadAllProducts扩展的AsyncTask＆LT;字符串，字符串，字符串＆GT; { / ** *启动后台线程显示进度对话框之前 * * / @覆盖 在preExecute保护无效（）{ super.on preExecute（）; pDialog =新ProgressDialog（AllProductsActivity.this）; pDialog.setMessage（加载产品请稍候......）; pDialog.setIndeterminate（假）; pDialog.setCancelable（假）; pDialog.show（）; } / ** *让所有的产品网址 * * / 保护字符串doInBackground（字符串参数... args）{ //大厦参数 清单＆LT;＆的NameValuePair GT; PARAMS =新的ArrayList＆LT;＆的NameValuePair GT;（）; // URL从获取JSON字符串 JSONObject的JSON = jParser.makeHtt prequest（url_all_products，GET，则params）; //检查JSON效应初探日志的猫 Log.d（所有产品，json.toString（））; 尝试{ //检查成功TAG INT成功= json.getInt（TAG_SUCCESS）; 如果（成功== 1）{ 发现//产品 //获取产品阵列 产品= json.getJSONArray（TAG_PRODUCTS）; //产品通过所有循环 的for（int i = 0; I＆LT; products.length（）;我++）{ JSONObject的C = products.getJSONObject（I） //存储在变量中的每个JSON项目 字符串ID = c.getString（TAG_PID）; 字符串名称= c.getString（TAG_NAME）; //创建新的HashMap HashMap的＆LT;字符串，字符串＆GT;地图=新的HashMap＆LT;字符串，字符串＆GT;（）; //将每个子节点的HashMap键=＆GT;值 map.put（TAG_PID，身份证）; map.put（TAG_NAME，名）; //添加HashList到ArrayList的 productsList.add（地图）; } }其他{ //没有发现产品 //启动添加新产品活动 意图I =新意图（getApplicationContext（） NewProductActivity.class）; //关闭所有previous活动 i.addFlags（Intent.FLAG_ACTIVITY_CLEAR_TOP）; startActivity（ⅰ）; } }赶上（JSONException E）{ e.printStackTrace（）; } 返回null; } / ** *在完成后台任务之后辞退进度对话框 * ** / 保护无效onPostExecute（字符串FILE_URL）{ //让所有的产品后，关闭该对话框 pDialog.dismiss（）; //从后台线程更新界面 runOnUiThread（新的Runnable（）{ 公共无效的run（）{ / ** *更新解析JSON数据到ListView控件 * * / ListAdapter适配器=新SimpleAdapter（ AllProductsActivity.this，产品列表， R.layout.list_item，新的String [] {TAG_PID， TAG_NAME}， 新的INT [] {R.id.pid，R.id.name}）; //更新列表视图 setListAdapter（适配器）; } }）; } }} 问题是excatly触发执行这条线时：
//获取JSON从URL字符串 JSONObject的JSON = jParser.makeHtt prequest（url_all_products，GET，则params）; 这是怎么回事与code？我想，我不是编码有些不妥。任何帮助吗？
PHP文件：
＆LT; PHP的头？（'内容类型：应用程序/ JSON的;字符集= utf-8'）;/ * *继code将列出所有产品 * ///数组JSON响应$响应=阵列（）;//其中包括DB连接类require_once __DIR__。 /db_connect.php';//连接到数据库$ DB =新DB_CONNECT（）;//从产品表中的所有产品$结果= mysql_query（SELECT * FROM产品）或死亡（mysql_error（））;//检查空结果如果（mysql_num_rows（$结果）大于0）{ //通过所有结果循环 //产品节点 $响应[产品] =阵列（）; 而（$行= mysql_fetch_array（$结果））{ //临时用户阵 $产品=阵列（）; $产品[PID] = $行[PID]; $产品[名称] = $行[名称]; $产品[价格] = $行[价格]; $产品[说明] = $行[说明]; $产品[created_at] = $行[created_at]; $产品[的updated_at] = $行[的updated_at]; //推单一产品到最终响应数组 array_push（$响应[产品]，$产品）; } //成功 $响应[成功] = 1; //呼应JSON响应 回声json_en code（$响应）;}其他{ //没有发现产品 $响应[成功] = 0; $响应[消息] =没有找到产品; //回声没有用户JSON 回声json_en code（$响应）;}？＆GT; 
解决方案
相反mashalling和自己和解组的对象，检查GSON图书馆，是由谷歌开发的。
HTTP：//$c$c.google.com/p/google -gson /
函数库的使用： https://sites.google.com/site/gson / GSON-用户指南
希望它帮助。
I'm facing that problem when trying to retrieving data from database:
Error parsing data org.json.JSONException: Value <!DOCTYPE of type java.lang.String cannot be converted to JSONObject
public class AllProductsActivity extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
private static String url_all_products = "http://192.168.1.3/android_connect/get_all_products.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "products";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
// products JSONArray
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_products);
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
// Get listview
ListView lv = getListView();
// on seleting single product
// launching Edit Product Screen
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String pid = ((TextView) view.findViewById(R.id.pid)).getText()
.toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
EditProductActivity.class);
// sending pid to next activity
in.putExtra(TAG_PID, pid);
// starting new activity and expecting some response back
startActivityForResult(in, 100);
}
});
}
// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AllProductsActivity.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
NewProductActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
AllProductsActivity.this, productsList,
R.layout.list_item, new String[] { TAG_PID,
TAG_NAME},
new int[] { R.id.pid, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
The problem is excatly triggering when executing that line:
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
What's going on with that code? I think that i'm not coding something wrong. Any help please?
PHP FILE:
<?php header('content-type: application/json; charset=utf-8');
/*
* Following code will list all the products
*/
// array for JSON response
$response = array();
// include db connect class
require_once __DIR__ . '/db_connect.php';
// connecting to db
$db = new DB_CONNECT();
// get all products from products table
$result = mysql_query("SELECT * FROM products") or die(mysql_error());
// check for empty result
if (mysql_num_rows($result) > 0) {
// looping through all results
// products node
$response["products"] = array();
while ($row = mysql_fetch_array($result)) {
// temp user array
$product = array();
$product["pid"] = $row["pid"];
$product["name"] = $row["name"];
$product["price"] = $row["price"];
$product["description"] = $row["description"];
$product["created_at"] = $row["created_at"];
$product["updated_at"] = $row["updated_at"];
// push single product into final response array
array_push($response["products"], $product);
}
// success
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
} else {
// no products found
$response["success"] = 0;
$response["message"] = "No products found";
// echo no users JSON
echo json_encode($response);
}
?>
解决方案
Instead of mashalling and unmarshalling your objects by yourself, check the Gson Library, developed by Google.
http://code.google.com/p/google-gson/
Library Usage: https://sites.google.com/site/gson/gson-user-guide
Hope it helps.
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