flex json的使用

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flex

1.json的源码:可以下载as3corelib核心包里面有详细的介绍

2.通过json的测试类,我们可以很容易的理解和使用json转义成任何flex对象

请看json的测试类 JSONTest.as,这里我就不解释了,内容比较的简单,

package com.adobe.serialization.json
{

import flexunit.framework.TestCase;

public class JSONTest extends TestCase {

     public function JSONTest( methodName:String = null) {
   super( methodName );
        }

  /**
   * Test for the JSON string true decoded to boolean true.
   */
  public function testDecodeTrue():void {
   var o:* = JSON.decode( " \n true \n " ) as Boolean;
   assertTrue( "Expected decoded true", o == true );
  }

  public function testDecodeFalse():void {
   var o:* = JSON.decode( " false " ) as Boolean;
   assertTrue( "Expected decoded false", o == false );
  }

  public function testDecodeNull():void
  {
   var o:* = JSON.decode( "null " );
   assertTrue( "Expected decoded null", o == null );
  }

  public function testDecodeString():void
  {
   var o:* = JSON.decode( ' "this is \t a string \n with \' escapes" ' ) as String;
   assertTrue( "String not decoded successfully", o == "this is \t a string \n with \' escapes" );

   o = JSON.decode( ' "http:\/\/digg.com\/security\/Simple_Digg_Hack" ' );
   assertTrue( "String not decoded correctly", o == "http://digg.com/security/Simple_Digg_Hack" );
  }

  public function testDecodeZero():void
  {
   var n:Number = JSON.decode( "0" ) as Number;
   assertEquals( n, 0 );
  }

  public function testDecodeZeroWithDigitsAfterIt():void
  {
   var parseError:JSONParseError = null;
   try
   {
    var n:Number = JSON.decode( "02" ) as Number;
   }
   catch ( e:JSONParseError )
   {
    parseError = e;
   }
   finally
   {
    //trace( parseError.message );
    assertNotNull( parseError );
   }
  }

  public function testDecodePositiveInt():void
  {
   var n:int = JSON.decode( "123871" ) as int;
   assertEquals( n, 123871 );
  }

  public function testDecodeNegativeInt():void
  {
   var n:int = JSON.decode( "-97123" ) as int;
   assertEquals( n, -97123 );
  }

  public function testDecodePositiveFloat():void
  {
   var n:Number = JSON.decode( "12.987324" ) as Number;
   assertEquals( n, 12.987324 );
  }

  public function testDecodeNegativeFloat():void
  {
   var n:Number = JSON.decode( "-1298.7324" ) as Number;
   assertEquals( n, -1298.7324 );
  }

  public function testDecodeFloatLeadingZeroError():void
  {
   var parseError:JSONParseError = null;
   try
   {
    var n:Number = JSON.decode( "-.2" ) as Number;
   }
   catch ( e:JSONParseError )
   {
    parseError = e;
   }
   finally
   {
    trace( parseError.message );
    assertNotNull( parseError );
   }
  }

  public function testDecodeFloatDecimalMissingError():void
  {
   var parseError:JSONParseError = null;
   try
   {
    var n:Number = JSON.decode( "1." );
   }
   catch ( e:JSONParseError )
   {
    parseError = e;
   }
   finally
   {
    // Make sure we caught a parse error since
    // there has to be numbers after the decimal
    assertNotNull( parseError );
   }
  }

  public function testDecodeScientificRegularExponent():void
  {
   var n:Number = JSON.decode( "6.02e2" ) as Number;
   assertEquals( n, 602 );

   n = JSON.decode( "-2e10" );
   assertEquals( n, -20000000000 );
   assertEquals( n, -2 * Math.pow( 10, 10 ) );
  }

  public function testDecodeScientificPositiveExponent():void
  {
   var n:Number = JSON.decode( "2E+9" ) as Number;
   assertEquals( n, 2 * Math.pow( 10, 9 ) );

   n = JSON.decode( "-2.2E+23" ) as Number;
   assertEquals( n, -2.2 * Math.pow( 10, 23 ) );
  }

  public function testDecodeScientificNegativeExponent():void
  {
   var n:Number = JSON.decode( "6.02e-23" ) as Number;
   assertEquals( n, 6.02 * Math.pow( 10, -23 ) );

   n = JSON.decode( "-4e-9" ) as Number;
   assertEquals( n, -4 * Math.pow( 10, -9 ) );

   n = JSON.decode( "0E-2" ) as Number;
   assertEquals( n, 0 );
  }

  public function testDecodeScientificExonentError():void
  {
   var parseError:JSONParseError = null;
   try
   {
    var n:Number = JSON.decode( "1e" );
   }
   catch ( e:JSONParseError )
   {
    parseError = e;
   }
   finally
   {
    // Make sure we caught a parse error since
    // there has to be numbers after the e
    assertNotNull( parseError );
   }
  }

// Commented out - this is something that should only be available when "strict" is
// false.
//  public function testDecodeHexNumber():void
//  {
//   var n:Number = JSON.decode( "0xFF0033" );
//   assertEquals( 0xFF0033, n );
//
//   var parseError:JSONParseError = null;
//   try
//   {
//    n = JSON.decode( "0xZ" );
//   }
//   catch ( e:JSONParseError )
//   {
//    parseError = e;
//   }
//   finally
//   {
//    // Make sure we catch a parse error since 0xZ is an invalid number
//    assertNotNull( parseError );
//   }
//  }

  public function testDecodeObject():void {
   var o:* = JSON.decode( " { \"test\": true, \"test2\": -12356732.12 } " ) as Object;
   assertTrue( "Expected decoded object.test = true", o.test == true );
   assertTrue( "Expected decoded object.test2 = -12356732.12", o.test2 == -12356732.12 );
  }

  public function testDecodeArray():void {
   var o:* = JSON.decode( " [ null, true, false, 100, -100, \"test\", { \"foo\": \"bar\" } ] " ) as Array;
   assertTrue( "Expected decoded array[0] == null", o[0] == null );
   assertTrue( "Expected decoded array[1] == true", o[1] == true );
   assertTrue( "Expected decoded array[2] == false", o[2] == false );
   assertTrue( "Expected decoded array[3] == 100", o[3] == 100 );
   assertTrue( "Expected decoded array[4] == -100", o[4] == -100 );
   assertTrue( "Expected decoded array[5] == \"test\"", o[5] == "test" );
   assertTrue( "Expected decoded array[6].foo == \"bar\"", o[6].foo == "bar" );
  }

  public function testDecodeArrayWithNewlines():void {
   var o:Array = JSON.decode( "\n [ \nnull, \n \r \t \r true \n ] \r \t \r \n" ) as Array;

   assertTrue( "Expected decoded with newlines array[0] == null", o[0] == null );
   assertTrue( "Expected decoded with newlines array[1] == true", o[1] == true );
  }

  public function testDecodeSuccessiveComments():void
  {
   var jsonString:String = "   // test comment"
       + "\n   // test comment line 2"
       + "\nfalse";
   var o:* = JSON.decode( jsonString );
   assertEquals( false, o );
  }

  public function testEncodeTrue():void {
   var o:String = JSON.encode( true );
   assertTrue( "Expected encoded true", o == "true" );
  }

  public function testEncodeFalse():void {
   var o:String = JSON.encode( false );
   assertTrue( "Expected encoded false", o == "false" );
  }

  public function testEncodeNull():void {
   var o:String = JSON.encode( null );
   assertTrue( "Expected encoded null", o == "null" );
  }

  public function testEncodeString():void {
   var o:String = JSON.encode( "this is a \n \"string\"" );
   assertTrue( "Expected encoded string", o == "\"this is a \\n \\\"string\\\"\"" );

   o = JSON.encode( "myString" );
   assertEquals( o, "\"myString\"" );
  }

  public function testEncodeArrayEmpty():void {
   var o:String = JSON.encode( [] );
   assertTrue( "Expected encoded []", o == "[]" );
  }

  public function testEncodeArray():void {
   var o:String = JSON.encode( [ true, false, -10, null, Number.NEGATIVE_INFINITY ] );
   assertTrue( "Expected encoded array", o == "[true,false,-10,null,null]" );
  }

  public function testEncodeObjectEmpty():void {
   var o:String = JSON.encode( {} );
   assertTrue( "Expected encoded {}", o == "{}" );
  }

  public function testEncodeObject():void {
   // Note: because order cannot be guaranteed when decoding
   // into a string, we can't reliably test an object with
   // multiple properties, so instead we test multiple
   // smaller objects
   //var obj:Object = new Object();
   //obj.test1 = true;
   //obj["test 2"] = false;
   //obj[" test _3" ] = { foo: "bar" };

   //var o:String = JSON.encode( obj );
   //assertTrue( "Expected encoded object", o == "{\"test1\":true,\"test 2\":false,\" test _3\":{\"foo\":\"bar\"}}" );

   var obj:Object = { foo: { foo2: { foo3: { foo4: "bar" } } } };
   var s:String = JSON.encode( obj );
   assertTrue( "Deeply nested", "{\"foo\":{\"foo2\":{\"foo3\":{\"foo4\":\"bar\"}}}}" );

   obj = new Object();
   obj[" prop with spaces "] = true;
   assertTrue( "Prop with spaces", "{\" prop with spaces \":true}" );
  }

  public function testEncodeClassInstance():void
  {
   var s:String = JSON.encode( new SimpleClass() );

   assertTrue( "Has length", s.length > 0 );

// Decode the string so we can verify that it has the properties
var o:Object = JSON.decode( s );

   assertNotNull( o );
   assertNotNull( o.publicVar1 );
   assertNotNull( o.publicVar2 );
   assertNotNull( o.accessor1 );
   assertNotNull( o.accessor2 );
   assertEquals( 17, o.publicVar1 );
   assertEquals( 20, o.publicVar2 );
   assertEquals( 25, o.accessor1 );
   assertEquals( 30, o.accessor2 );

   // Make sure o only has 4 properties
   var count:int = 0;
   for ( var key:String in o )
   {
    count++;
   }
   assertEquals( 4, count );
  }

  public function testDecodeEmptyStringError():void
  {
   var e:Error = null;

   try
   {
    JSON.decode( "" );
   }
   catch ( pe:JSONParseError )
   {
    e = pe;
   }

   assertNotNull( e );
   assertTrue( "Caught parse error", e is JSONParseError );
  }

  public function testWhiteSpace():void
  {
   /*
         ws = *(
                %x20 /              ; Space
                %x09 /              ; Horizontal tab
                %x0A /              ; Line feed or New line
                %x0D                ; Carriage return
            )
   */

   //tabs
   var a_tab:String = "[\t1\t]";

   var a_tab_result:Array = JSON.decode(a_tab) as Array;

   assertEquals(a_tab_result[0], 1);


   //space
   var a_space:String = "[ 1 ]";

   var a_space_result:Array = JSON.decode(a_space) as Array;

   assertEquals(a_space_result[0], 1);

   //line return
   var a_lr:String = "[\n1\n]";

   var a_lr_result:Array = JSON.decode(a_lr) as Array;

   assertEquals(a_lr_result[0], 1);

   //carriage return
   var a_cr:String = "[\r1\r]";

   var a_cr_result:Array = JSON.decode(a_cr) as Array;

   assertEquals(a_cr_result[0], 1);

   //combined return
   var a_clr:String = "[\n\r1\n\r]";

   var a_clr_result:Array = JSON.decode(a_clr) as Array;

   assertEquals(a_clr_result[0], 1);
  }


}

}

比较有用的,而且需要注意的地方

var o:* = JSON.decode( " [ null, true, false, 100, -100, \"test\", { \"foo\": \"bar\" } ] " ) as Array;

在转换成数组的时候,{ \"foo\": \"bar\" } 对象的属性值需转义为字符串!不能写成如下:{foo: \"bar\" }

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