<转>基于json-lib.jar包Json范例程序

<转>基于json-lib.jar包Json实例程序
原链：http://www.cnblogs.com/langtianya/archive/2013/04/09/3009235.html

基于json-lib.jar包Json实例程序1.JSONObject to DynaBeanString json = "{name="json",bool:true,int:1,double:2.2}";JSONObject jsonObject = JSONObject.fromObject(json);//抽象的写法：DynaBean bean = (DynaBean) JSONSerializer.toJava( jsonObject ); Object bean = JSONObject.toBean(jsonObject);//Object bean1 = JSONSerializer.toJava(jsonObject);assertEquals(jsonObject.get("name"), PropertyUtils.getProperty(bean, "name"));assertEquals(jsonObject.get("bool"), PropertyUtils.getProperty(bean, "bool"));assertEquals(jsonObject.get("int"), PropertyUtils.getProperty(bean, "int"));assertEquals(jsonObject.get("double"), PropertyUtils.getProperty(bean, "double"));2.JSONObject to JavaBeanString json = "{name:"zhangsan",age:25,hight:1.72,sex:true}";JSONObject jsonObject = JSONObject.fromObject(json);UserBean bean = (UserBean) JSONObject.toBean(jsonObject, UserBean.class);System.out.println(jsonObject);理论上，这样就可以了，但时，有异常Caused by: java.lang.NoSuchMethodException: com.json.Json$UserBean.<init>()3.JSONArray to ListString json = "["first","second"]";JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(json);List output = (List) JSONSerializer.toJava(jsonArray);4.JSONArray to arrayString json = "["first","second"]";JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(json);JsonConfig jsonConfig = new JsonConfig();jsonConfig.setArrayMode(JsonConfig.MODE_OBJECT_ARRAY);Object[] output = (Object[]) JSONSerializer.toJava(jsonArray, jsonConfig);Object[] expected = new Object[] { "first", "second" };ArrayAssertions.assertEquals(expected, output);5.JSON 字符串 专为 JavaBean（刘慧斌demo 演示需要的jar包在附件里）String str="[{"id":"328","mestype":"inbox"},{"id":"327","mestype":"inbox"},{"id":"279","mestype":"already"},{"id":"278","mestype":"already"},{"id":"277","mestype":"already"},{"id":"310","mestype":"inbox"},{"id":"308","mestype":"inbox"},{"id":"305","mestype":"inbox"},{"id":"304","mestype":"inbox"},{"id":"303","mestype":"inbox"}]";JSONArray jsonArray=(JSONArray) JSONSerializer.toJSON(str);List list=(List)JSONSerializer.toJava(jsonArray);for (Object obj: list) {JSONObject jsonObject = JSONObject.fromObject(obj);MessageBean bean = (MessageBean) JSONObject.toBean(jsonObject, MessageBean.class);String id=bean.getId()+"";String type=bean.getMestype();System.out.println(id+" "+type);}System.out.println(list.size());

http://blog.sina.com.cn/s/blog_9d0ce63d01012vmd.html  JacksonDemo及使用方法


本文依据springside实例，演示Jackson的基本使用方式及大量的特殊Feature.一共13种使用方法。

public class JsonDemo { private static JsonMapper mapper = JsonMapper.buildNonDefaultMapper(); 1、序列化对象/集合到Json字符串.@Test public void toJson() throws Exception {  //Bean  TestBean bean = new TestBean("A");  String beanString = mapper.toJson(bean);  System.out.println("Bean:" + beanString);  assertEquals("{"name":"A"}", beanString);  //Map  Map<String, Object> map = Maps.newLinkedHashMap();  map.put("name", "A");  map.put("age", 2);  String mapString = mapper.toJson(map);  System.out.println("Map:" + mapString);  assertEquals("{"name":"A","age":2}", mapString);  //List<String>  List<String> stringList = Lists.newArrayList("A", "B", "C");  String listString = mapper.toJson(stringList);  System.out.println("String List:" + listString);  assertEquals("["A","B","C"]", listString);  //List<Bean>  List<TestBean> beanList = Lists.newArrayList(new TestBean("A"), new TestBean("B"));  String beanListString = mapper.toJson(beanList);  System.out.println("Bean List:" + beanListString);  assertEquals("[{"name":"A"},{"name":"B"}]", beanListString);  //Bean[]  TestBean[] beanArray = new TestBean[] { new TestBean("A"), new TestBean("B") };  String beanArrayString = mapper.toJson(beanArray);  System.out.println("Array List:" + beanArrayString);  assertEquals("[{"name":"A"},{"name":"B"}]", beanArrayString);}   2、从Json字符串反序列化对象/集合. @Test public void fromJson() throws Exception {  //Bean  String beanString = "{"name":"A"}";  TestBean bean = mapper.fromJson(beanString, TestBean.class);  System.out.println("Bean:" + bean);  //Map  String mapString = "{"name":"A","age":2}";  Map<String, Object> map = mapper.fromJson(mapString, HashMap.class);  System.out.println("Map:");  for (Entry<String, Object> entry : map.entrySet()) {   System.out.println(entry.getKey() + " " + entry.getValue());  }  //List<String>  String listString = "["A","B","C"]";  List<String> stringList = mapper.fromJson(listString, List.class);  System.out.println("String List:");  for (String element : stringList) {   System.out.println(element);  }  //List<Bean>  String beanListString = "[{"name":"A"},{"name":"B"}]";  JavaType beanListType = mapper.constructParametricType(List.class, TestBean.class);  List<TestBean> beanList = mapper.fromJson(beanListString, beanListType);  System.out.println("Bean List:");  for (TestBean element : beanList) {   System.out.println(element);  } } 3、 测试三种不同的Binder.   @Test public void threeTypeBinders() {  TestBean bean = new TestBean("A");  //打印全部属性  JsonMapper normalMapper = JsonMapper.buildNormalMapper();  assertEquals("{"nullValue":null,"name":"A","defaultValue":"hello"}", normalMapper.toJson(bean));  //不打印nullValue属性  JsonMapper nonNullMapper = JsonMapper.buildNonNullMapper();  assertEquals("{"name":"A","defaultValue":"hello"}", nonNullMapper.toJson(bean));  //不打印默认值未改变的nullValue与defaultValue属性  JsonMapper nonDefaultMaper = JsonMapper.buildNonDefaultMapper();  assertEquals("{"name":"A"}", nonDefaultMaper.toJson(bean)); }4、测试传入空对象,空字符串,Empty的集合,"null"字符串的结果.   @Test public void nullAndEmpty() {  // toJson测试 //  //Null Bean  TestBean nullBean = null;  String nullBeanString = mapper.toJson(nullBean);  assertEquals("null", nullBeanString);  //Empty List  List<String> emptyList = Lists.newArrayList();  String emptyListString = mapper.toJson(emptyList);  assertEquals("[]", emptyListString);  // fromJson测试 //  //Null String for Bean  TestBean nullBeanResult = mapper.fromJson(null, TestBean.class);  assertNull(nullBeanResult);  nullBeanResult = mapper.fromJson("null", TestBean.class);  assertNull(nullBeanResult);  //Null/Empty String for List  List nullListResult = mapper.fromJson(null, List.class);  assertNull(nullListResult);  nullListResult = mapper.fromJson("null", List.class);  assertNull(nullListResult);  nullListResult = mapper.fromJson("[]", List.class);  assertEquals(0, nullListResult.size()); }5、测试对枚举的序列化,可以选择用一个int字段而不是以Name来序列化，以减少少长度.  @Test public void enumData() {  //默認使用enum.name()  assertEquals(""One"", mapper.toJson(TestEnum.One));  assertEquals(TestEnum.One, mapper.fromJson(""One"", TestEnum.class));  //使用enum.toString()  //注意，index會通過toString序列成字符串而不是int,否則又和順序號混淆.  //注意配置必須在所有讀寫動作之前調用.  JsonMapper newMapper = JsonMapper.buildNormalMapper();  newMapper.setEnumUseToString(true);  assertEquals(""1"", newMapper.toJson(TestEnum.One));  assertEquals(TestEnum.One, newMapper.fromJson(""1"", TestEnum.class)); } 枚举的演示Bean. public static enum TestEnum {  One(1), Two(2), Three(3);  private int index;  TestEnum(int index) {   this.index = index;  }  @Override  public String toString() {   return new Integer(index).toString();  } }6、测试对日期的序列化.@Test public void dateData() {  DateTime jodaDate = new DateTime();  //日期默认以Timestamp方式存储  Date date = new Date(jodaDate.getMillis());  String tsString = String.valueOf(jodaDate.getMillis());  assertEquals(tsString, mapper.toJson(date));  assertEquals(date, mapper.fromJson(tsString, Date.class)); }7、 JSON字符串里只含有Bean中部分的属性，更新一个已存在Bean，只覆蓋部分的属性.  @Test public void updateBean() {  String jsonString = "{"name":"A"}";  TestBean bean = new TestBean();  bean.setDefaultValue("Foobar");  bean = mapper.update(bean, jsonString);  assertEquals("A", bean.getName());  assertEquals("Foobar", bean.getDefaultValue()); }8、测试父子POJO间的循环引用.@Test public void parentChildBean() {  //初始化对象关系，parent的Childs里含有 child1,child2, child1/child2的parent均指向parent.  ParentChildBean parent = new ParentChildBean("parent");  ParentChildBean child1 = new ParentChildBean("child1");  child1.setParent(parent);  parent.getChilds().add(child1);  ParentChildBean child2 = new ParentChildBean("child2");  child2.setParent(parent);  parent.getChilds().add(child2);  String jsonString = "{"childs":[{"name":"child1"},{"name":"child2"}],"name":"parent"}";  //打印parent的json输出，json字符串裡childs中的child1/child2都不包含到parent的屬性  assertEquals(jsonString, mapper.toJson(parent));  //注意此時如果單獨打印child1，也不會打印parent，信息將丟失。  assertEquals("{"name":"child1"}", mapper.toJson(child1));  //反向序列化时，Json已很聪明的把parent填入child1/child2中.  ParentChildBean parentResult = mapper.fromJson(jsonString, ParentChildBean.class);  assertEquals("parent", parentResult.getChilds().get(0).getParent().getName()); }父子POJO父子POJO的演示Bean,@JsonBackReference 与 @JsonManagedReference 是关键. public static class ParentChildBean {  private String name;  private ParentChildBean parent;  public List<ParentChildBean> childs = Lists.newArrayList();  public ParentChildBean() {  }  public ParentChildBean(String name) {   this.name = name;  }  public String getName() {   return name;  }  public void setName(String name) {   this.name = name;  }  //注意getter與setter都要添加annotation  @JsonBackReference  public ParentChildBean getParent() {   return parent;  }  @JsonBackReference  public void setParent(ParentChildBean parent) {   this.parent = parent;  }  @JsonManagedReference  public List<ParentChildBean> getChilds() {   return childs;  }  @JsonManagedReference  public void setChilds(List<ParentChildBean> childs) {   this.childs = childs;  } } 9、測試可擴展Bean,會自動的把確定的屬性放入固定的成員變量, 其他屬性放到一个类型为Map的成员变量裡,能很好的支持Bean版本升级时固定属性的变动.  @Test public void extensibleBean() {  //一个没有区分是变量还是Map的普通JSON字符串.  String jsonString = "{"name" : "Foobar","age" : 37,"occupation" : "coder man"}";  ExtensibleBean extensibleBean = mapper.fromJson(jsonString, ExtensibleBean.class);  assertEquals("Foobar", extensibleBean.getName());  assertEquals(null, extensibleBean.getProperties().get("name"));  assertEquals("coder man", extensibleBean.getProperties().get("occupation")); }演示用的可擴展Bean.@JsonAnySetter与@JsonAnyGetter是关键.  public static class ExtensibleBean {  private String name; // we always have name  private HashMap<String, String> properties = Maps.newHashMap();  public ExtensibleBean() {  }  @JsonAnySetter  public void add(String key, String value) {   properties.put(key, value);  }  @JsonAnyGetter  public Map<String, String> getProperties() {   return properties;  }  public String getName() {   return name;  }  public void setName(String name) {   this.name = name;  } } 10、測試序列化Bean时使用不同的View序列化不同的属性组, 及@JsonIgnore標註的屬性.@Test public void viewBean() throws JsonGenerationException, JsonMappingException, IOException {  ViewBean viewBean = new ViewBean();  viewBean.setName("Foo");  viewBean.setAge(16);  viewBean.setOtherValue("others");  viewBean.setIgnoreValue("ignored");  ObjectWriter publicWriter = mapper.getMapper().writerWithView(Views.Public.class);  assertEquals("{"otherValue":"others","name":"Foo"}", publicWriter.writeValueAsString(viewBean));  ObjectWriter internalWriter = mapper.getMapper().writerWithView(Views.Internal.class);  assertEquals("{"age":16,"otherValue":"others"}", internalWriter.writeValueAsString(viewBean));  //設置默認是否顯示沒有用@Json定義的屬性  JsonMapper newMapper = JsonMapper.buildNormalMapper();  newMapper.getMapper().configure(SerializationConfig.Feature.DEFAULT_VIEW_INCLUSION, false);  publicWriter = newMapper.getMapper().writerWithView(Views.Public.class);  assertEquals("{"name":"Foo"}", publicWriter.writeValueAsString(viewBean)); } public static class Views {  static class Public {  }  static class Internal {  } }  演示序列化不同View不同属性的Bean. public static class ViewBean {  private String name;  private int age;  private String otherValue;  private String ignoreValue;  @JsonView(Views.Public.class)  public String getName() {   return name;  }  public void setName(String name) {   this.name = name;  }  @JsonView(Views.Internal.class)  public int getAge() {   return age;  }  public void setAge(int age) {   this.age = age;  }  public String getOtherValue() {   return otherValue;  }  public void setOtherValue(String otherValue) {   this.otherValue = otherValue;  }  @JsonIgnore  public String getIgnoreValue() {   return ignoreValue;  }  public void setIgnoreValue(String ignoreValue) {   this.ignoreValue = ignoreValue;  } } 11、 测试自定义转换器  @Test public void customConverter() {  JsonMapper newMapper = JsonMapper.buildNonNullMapper();  SimpleModule testModule = new SimpleModule("MyModule", new Version(1, 0, 0, null));  testModule.addSerializer(new MoneySerializer()); // assuming serializer declares correct class to bind to  testModule.addDeserializer(Money.class, new MoneyDeserializer());  newMapper.getMapper().registerModule(testModule);  Money money = new Money(1.2);  String jsonString = newMapper.toJson(money);  assertEquals(""1.2"", jsonString);  Money resultMoney = newMapper.fromJson(jsonString, Money.class);  assertEquals(new Double(1.2), resultMoney.value); } public class MoneySerializer extends SerializerBase<Money> {  public MoneySerializer() {   super(Money.class);  }  public void serialize(Money value, JsonGenerator jgen, SerializerProvider provider) throws IOException,    JsonProcessingException {   jgen.writeString(value.toString());  } } public class MoneyDeserializer extends StdDeserializer<Money> {  public MoneyDeserializer() {   super(Money.class);  }  @Override  public Money deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException,    JsonProcessingException {   return Money.valueOf(jp.getText());  } } public static class Money {  private Double value;  public Money(Double value) {   this.value = value;  }  public static Money valueOf(String value) {   Double srcValue = Double.valueOf(value);   return new Money(srcValue);  }  public String toString() {   return value.toString();  } } 12、测试修改属性名策略  @Test public void customPropertyNameing() throws JsonMappingException {  TestBean bean = new TestBean("foo");  bean.setDefaultValue("bar");  JsonMapper newMapper = JsonMapper.buildNonNullMapper();  newMapper.getMapper().setPropertyNamingStrategy(new LowerCaseNaming());  String jsonpString = newMapper.toJson(bean);  assertEquals("{"name":"foo","defaultvalue":"bar"}", jsonpString); } public static class LowerCaseNaming extends PropertyNamingStrategy {  @Override  public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName) {   return defaultName.toLowerCase();  } } 13、 測試輸出jsonp格式內容.@Test public void jsonp() {  TestBean bean = new TestBean("foo");  String jsonpString = mapper.toJsonP("callback", bean);  assertEquals("callback({"name":"foo"})", jsonpString); }  演示Bean, 主要演示不同風格的Mapper對Null值，初始化後沒改變過的屬性值的處理.   public static class TestBean {  private String name;  private String defaultValue = "hello"; //默认值没被修改过的属性，可能会不序列化  private String nullValue = null; //空值的据行，可能会不序列化  public TestBean() {  }  public TestBean(String name) {   this.name = name;  }  public String getName() {   return name;  }  public void setName(String name) {   this.name = name;  }  public String getDefaultValue() {   return defaultValue;  }  public void setDefaultValue(String defaultValue) {   this.defaultValue = defaultValue;  }  public String getNullValue() {   return nullValue;  }  public void setNullValue(String nullValue) {   this.nullValue = nullValue;  }  @Override  public String toString() {   return "TestBean [defaultValue=" + defaultValue + ", name=" + name + ", nullValue=" + nullValue + "]";  } }}

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