日期:2014-05-16 浏览次数:20358 次
public class JsonBinder { private static Logger logger = LoggerFactory.getLogger(JsonBinder.class); private ObjectMapper mapper; public JsonBinder(Inclusion inclusion) { mapper = new ObjectMapper(); //设置输出包含的属性 mapper.getSerializationConfig().setSerializationInclusion(inclusion); //设置输入时忽略JSON字符串中存在而Java对象实际没有的属性 mapper.getDeserializationConfig().set( org.codehaus.jackson.map.DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false); } /** * 创建输出全部属性到Json字符串的Binder. */ public static JsonBinder buildNormalBinder() { return new JsonBinder(Inclusion.ALWAYS); } /** * 创建只输出非空属性到Json字符串的Binder. */ public static JsonBinder buildNonNullBinder() { return new JsonBinder(Inclusion.NON_NULL); } /** * 创建只输出初始值被改变的属性到Json字符串的Binder. */ public static JsonBinder buildNonDefaultBinder() { return new JsonBinder(Inclusion.NON_DEFAULT); } /** * 如果JSON字符串为Null或"null"字符串,返回Null. * 如果JSON字符串为"[]",返回空集合. * * 如需读取集合如List/Map,且不是List<String>这种简单类型时使用如下语句: * List<MyBean> beanList = binder.getMapper().readValue(listString, new TypeReference<List<MyBean>>() {}); */ public <T> T fromJson(String jsonString, Class<T> clazz) { if (StringUtils.isEmpty(jsonString)) { return null; } try { return mapper.readValue(jsonString, clazz); } catch (IOException e) { logger.warn("parse json string error:" + jsonString, e); return null; } } /** * 如果对象为Null,返回"null". * 如果集合为空集合,返回"[]". */ public String toJson(Object object) { try { return mapper.writeValueAsString(object); } catch (IOException e) { logger.warn("write to json string error:" + object, e); return null; } } /** * 设置转换日期类型的format pattern,如果不设置默认打印Timestamp毫秒数. */ public void setDateFormat(String pattern) { if (StringUtils.isNotBlank(pattern)) { DateFormat df = new SimpleDateFormat(pattern); mapper.getSerializationConfig().setDateFormat(df); mapper.getDeserializationConfig().setDateFormat(df); } } /** * 取出Mapper做进一步的设置或使用其他序列化API. */ public ObjectMapper getMapper() { return mapper; } }
private static JsonBinder binder = JsonBinder.buildNonDefaultBinder();
/** * 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 = binder.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 = binder.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 = binder.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 = binder.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 = binder.toJson(beanArray); System.out.println("Array List:" + beanArrayString); assertEquals("[{\"name\":\"A\"},{\"name\":\"B\"}]", beanArrayString); } /** * 从Json字符串反序列化对象/集合. */ @Test @SuppressWarnings("unchecked") public void fromJson() throws Exception { //Bean String beanString = "{\"name\":\"A\"