客户端如何写一个ajax请求，来读取php传递出的json数据（为浮点型）？然后可以与文本框输入的数据比较？

在服务器将数据转换为JOSN格式

由于数据库储存的数据（一般情况下）是不变的，将返回的结果储存到数组中（用定时器太烧性能）

server.php服务端：

        //将数据库获取的数据转换为Json格式并返回前端

        $json = array()   //先定义一个空数组来存储。

        while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {

            array_push($json, array("id" => $row['id'], "name" => $row['name']))  //其他数据自己补充

        }

        echo json_encode(array("json" => $json))

前端：

    $(document).ready(function(){

                $.getJSON("http://web.thinkphp.com/jjaiyy1", function(data){

                     var array = data.json.slice()  //数据克隆

                })

    })

比较输入大小，用循环跟数组比较。

全栈之路不好走

因为这次要从服务器端得到Json数据,并且通过解析之后把解析后的数据显示在Android客户端中,首先部署服务器端代码(直接使用Jsp/Servlet):

构造的Json数据如下:

[{"name":"张三","address":"北京","age":20},{"name":"李四","address":"上海","age":30},{"name":"王五","address":"深圳","age":35}]

[一]服务器端(Person.java省略):

①:数据构造JsonService.java

public class JsonService {

public static List<Person>getListPerson() {

List<Person>mLists = new ArrayList<Person>()

mLists.add(new Person("张三", "北京", 20))

mLists.add(new Person("李四", "上海", 30))

mLists.add(new Person("王五", "深圳", 35))

return mLists

}

②:Servlet的代码（包括构造Json数据，没有使用Json数据转换方法）JsonServlet.java

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html")

response.setCharacterEncoding("UTF-8")

PrintWriter out = response.getWriter()

List<Person>persons = JsonService.getListPerson()

StringBuffer sb = new StringBuffer()

sb.append('[')

for (Person person : persons) {

sb.append('{').append("\"name\":").append("\""+person.getName()+"\"").append(",") sb.append("\"address\":").append("\""+person.getAddress()+"\"").append(",")

sb.append("\"age\":").append(person.getAge())

sb.append('}').append(",")

}

sb.deleteCharAt(sb.length() - 1)

sb.append(']')

out.write(new String(sb))

out.flush()

out.close()

}

③:部署到Tomact 浏览器输入http://localhost/JsonWeb/JsonServlet直接访问结果如下:

[{"name":"张三","address":"北京","age":20},{"name":"李四","address":"上海","age":30},{"name":"王五","address":"深圳","age":35}]

至此服务器端代码编码完成，下面进行客户端代码编写 (二)客户端(Person类，和展示数据的布局文件因为简单省去) ①:获取服务器端的Json数据并且解析的工具类JsonParse.java 必要的需要导入的包省去

public class JsonParse {

/**

* 解析Json数据

*

* @param urlPath

* @return mlists

* @throws Exception

*/

public static List<Person>getListPerson(String urlPath) throws Exception {

List<Person>mlists = new ArrayList<Person>()

byte[] data = readParse(urlPath)

JSONArray array = new JSONArray(new String(data))

for (int i = 0i <array.length()i++) {

JSONObject item = array.getJSONObject(i)

String name = item.getString("name")

String address = item.getString("address")

int age = item.getInt("age")

mlists.add(new Person(name, address, age))

}

return mlists

}

/**

* 从指定的url中获取字节数组

*

* @param urlPath

* @return 字节数组

* @throws Exception

*/

public static byte[] readParse(String urlPath) throws Exception {

ByteArrayOutputStream outStream = new ByteArrayOutputStream()

byte[] data = new byte[1024]

int len = 0

URL url = new URL(urlPath)

HttpURLConnection conn = (HttpURLConnection) url.openConnection()

InputStream inStream = conn.getInputStream()

while ((len = inStream.read(data)) != -1) {

outStream.write(data, 0, len)

}

inStream.close()

return outStream.toByteArray()

}

}

②:主Activity类

public class MainActivity extends Activity {

private Button mButton

private ListView mListView

//使用IP不能使用localhost或者127.0.0.1，因为android模拟器默认绑定这个IP，这里应该访问局域网IP

private static final String urlPath = "http://10.16.31.207/JsonWeb/JsonServlet"

private static final String TAG = "MainActivity"

private List<Person>persons

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState)

setContentView(R.layout.main)

mButton = (Button) findViewById(R.id.button1)

mListView = (ListView) findViewById(R.id.listView1)

mButton.setOnClickListener(new MyOnClickListener())

}

private class MyOnClickListener implements OnClickListener {

@Override

public void onClick(View v) {

try {

// 得到Json解析成功之后数据

persons = JsonParse.getListPerson(urlPath)

List<HashMap<String, Object>>data = new ArrayList<HashMap<String, Object>>()

for (int i = 0i <persons.size()i++) {

HashMap<String, Object>map = new HashMap<String, Object>()

map.put("name", persons.get(i).getName())

map.put("address", persons.get(i).getAddress())

map.put("age", persons.get(i).getAge())

data.add(map)

}

//初始化适配器，并且绑定数据

SimpleAdapter _Adapter = new SimpleAdapter(MainActivity.this,

data, R.layout.listview_item, new String[] { "name",

"address", "age" }, new int[] { R.id.textView1,

R.id.textView2, R.id.textView3 })

mListView.setAdapter(_Adapter)

} catch (Exception e) {

Toast.makeText(MainActivity.this, "解析失败", 2000).show()

Log.i(TAG, e.toString())

}

}

}

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