ajax和json
ajax 的使用不必多说 ,
触发事件 ,
创建ajax,
然后open向后台发送信息 ,
后台获取信息判断 , 返回信息 ,
前台再进行判断!
json的使用
Json-lib 是一个 Java 类库(官网:http://json-lib.sourceforge.net/)可以实现如下功能:
转换 javabeans, maps, collections, java arrays 和 XML 成为 json 格式数据
转换 json 格式数据成为 javabeans 对象
Json-lib 需要的 jar 包
commons-beanutils-1.8.3.jar
commons-collections-3.2.1.jar
commons-lang-2.6.jar
commons-logging-1.1.1.jar
ezmorph-1.0.6.jar
json-lib-2.4-jdk15.jar
/** * 将单列集合或数组转化为json */ @Test public void demo1() { String[] str = {"jack","tom","90","true"}; JSONArray json = JSONArray.fromObject(str); System.out.println(json); Object[] arr = {"jack","tom","90","true"}; JSONArray json1 = JSONArray.fromObject(arr); System.out.println(json1); List<String> list =new ArrayList<String>(); list.add("tom"); list.add("jack"); list.add("90"); list.add("true"); JSONArray json2 = JSONArray.fromObject(list); System.out.println(json2); Set<String> set = new HashSet<String>(); set.add("tom"); set.add("jack"); set.add("90"); set.add("true"); JSONArray json3 = JSONArray.fromObject(set); System.out.println(json3); } /** * 将双列集合map或者javaBean转换为json */ @Test public void demo2(){ // 改造map Map<String, Object> map = new HashMap<String, Object>(); map.put("name", "tom"); map.put("age", 90); JSONObject json = JSONObject.fromObject(map); System.out.println(json); //改造javaBean Person person = new Person("a001","tom"); JSONObject json1 = JSONObject.fromObject(person); System.out.println(json1); //解析嵌套的对象 map.put("person", person); JSONObject json2 = JSONObject.fromObject(map); System.out.println(json2); } /** * 用JsonConfig来调整双列集合或javaBean显示哪些数据 */ @Test public void demo3() { JsonConfig config = new JsonConfig(); config.setExcludes(new String[] {"name"}); Person person = new Person("a001","tom"); JSONObject json = JSONObject.fromObject(person, config); System.out.println(json); } /** * 4. 将 Json 串转成 Array */ @Test public void demo4() { String str = "[50,'tom',true]"; JSONArray json = JSONArray.fromObject(str); Object array = JSONArray.toArray(json); List<Object> list = Arrays.asList((Object[]) array); System.out.println(list); } /** * 5. 将 Json 串转成 JavaBean/Map: */ @Test public void demo5() { String str = "{'name':'Tom','age':90}"; JSONObject json = JSONObject.fromObject(str); Map<String, Object> p = (Map<String, Object>) JSONObject.toBean(json, Map.class); System.out.println(p); String str1 = "{'id':'a001','name':'tom'}"; JSONObject json1 = JSONObject.fromObject(str1); System.out.println(json1); Person person = (Person) JSONObject.toBean(json1, Person.class); System.out.println(person); } @Test public void demo6() { Map<Person,Integer> cart = new HashMap<Person, Integer>(); Integer i = cart.get(new Person()); System.out.println(i); }