ajax,json

Ajax operations

Create XMLHttpRequest object

XT = var null ;
   // Step ajax engine objects obtained 
  IF (window.XMLHttpRequest) { // create objects ajax The browser version 
XT = new new the XMLHttpRequest (); // create a new version of embodiment 
  } the else { 
XT = new new ActiveXObject ( "Microsoft.XMLHTTP"); // old way to create versions 
  }

The state is bound to trigger a function

 // Step bind listening 
  xt.onreadystatechange = Call; // here to force a callback function

Establish a connection to the server using the open method

 // Step bound address 
  xt.open ( "the GET", "/ AjaxTest / AjaxServlet name = Colin?", To true );
     // first parameter refers to a request for the second argument refers to the first path refers to the three parameters is not true false synchronous asynchronous 
  xt.open ( "the POST", "/ AjaxTest / AjaxServlet", to true ); 
    POST request method 
xt.setRequestHeader ( "the Content-the Type", "file application / X-WWW-form -urlencoded " ); 
    also need to add a request header 
    meaning indicating encoding client submitted to the server are URL encoded text

Send data to the server

get request mode 
xt.send (); 
    

POST request method 
xt.send ( "username =" + name);

Processing the data callback function returns

   // create a callback function 
does not determine the state before the 
      function Call () { 
     var text =   xt.responseText; 
     Alert (text); 
      } 
status determination based on 
    // the HTTP server response status code [200_ normal; [400 angstroms e.g. request error: request syntax]; 403_ no access; 404_ access the resource does not exist; 500_ internal server error}
     // properties readystate response status codes the XMLHttpRequest object 5 5 [0_XMLHttpRequest has not completed initialization; 1_XMLHttpRequest object starts transmission request; 2_XMLHttpRequest object request transmission completed; 3_XMLHttpRequest object starts to read response; 4_XMLHttpRequest object read response ends] 
after determining the state of 
      function Call () { 
      IF (xt.readyState == == 200 is xt.status &&. 4 ) { 
     var text =   xt.responseText ; 
     Alert (text); 
      } 
      }

The sample code

<input type = "button" value = "get request" the onclick = "Test ()"> </ Button> 
  <Script> 
      var XT = null ; 
      var A = 0 ; 
    function Test () { 

        IF (window.XMLHttpRequest) { 
            XT = new new the XMLHttpRequest (); 


        } the else { 
            XT = new new the ActiveXObject ( "Microsoft.XMHTTP" ); 
        } 

        //// properties readystate the response status code 5 in the XMLHttpRequest object 5
         // [0_XMLHttpRequest not completed initialization;
         // 1_XMLHttpRequest Object start sending requests;
         //2_XMLHttpRequest object request to send completed;
         // 3_XMLHttpRequest object begins to read the response;
         // 4_XMLHttpRequest object read response ends]
         // change the state of the trigger onreadystatechange method 

        xt.onreadystatechange = Call; 

        xt.open ( "GET", "/ the Upload? = ZYM name ", to true ) 
        xt.send () 


    } 

    function Call () { 
      IF (xt.readyState == == 200 is xt.status. 4 & ) {
           // add this condition must be determined to take a value 
          var the responseText = XT. the responseText;
           // the console.log (the responseText); 
          Alert (+ the responseText) 
      } 

    }




  </script>

json

Import jar package

commons-beanutils.jar provides java reflection packet
commons-collections.jar collections extended package
commons-lang.jar Enhanced Kit
commons-logging.jar provides a package of the log implemented
ezmorph-1.0.4.jar
JSON-lib -2.2.2-jdk15.jar

Pserson the object into a string json

public static String objectToJson(Person p){
String str = null;
JSONObject jo = JSONObject.fromObject(p);
str = jo.toString();//转成字符串
return str;
}

Converting the string to an object json

public  static the Person jsonToPerson (String STR) {
 // first string into a string json 
the JSONObject Object = JSONObject.fromObject (STR);
 // in turn to the person object json string toBean (); 
the Person P = (the Person) the JSONObject .toBean (Object, the Person. class );
 return P; 
}

The collection of arrays is converted into json

public static String listToJson(List<Person> li){
String str = null;
JSONArray ja = JSONArray.fromObject(li);
str = ja.toString();
return str;
}

Converting the array into a set json

public  static List <the Person> jsonToList (String STR) { 
List <the Person> List = new new the ArrayList <the Person> (); // get a new set of objects 
the JSONArray JA = JSONArray.fromObject (STR); // now string converted into JSONArray 
JSONObject Jo = null ;
 for ( int I = 0; I <ja.size (); I ++) { // iterate JSONArray 
Jo = ja.getJSONObject (I); // get every JSONArray JSONObject in the 
list. the Add ((the Person) JSONObject.toBean (Jo, the Person. class )); // in converting each bundle JSONObject UN as an object to the collection 
}
 return List; 
}

Converting the array into an array json

public static Person[] jsonToArray(String str){
JSONArray ja = JSONArray.fromObject(str);
Person[] p  = (Person[]) JSONArray.toArray(ja, Person.class);
return p;
}

Converting the map to set string json

public static String mapToJson(Map<Integer,Person> m){
return JSONArray.fromObject(m).toString();
}