json_jackson_junit_demo.zip

package org.foo.jackson; import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.type.JavaType; import org.foo.bean.Person; import org.junit.Test; public class JsonUtils { private static ObjectMapper objectMapper = new ObjectMapper(); public static <T> String bean2Json(T bean) { try { return objectMapper.writeValueAsString(bean); } catch (Exception e) { e.printStackTrace(); } return ""; } public static String map2Json(Map map) { try { return objectMapper.writeValueAsString(map); } catch (Exception e) { e.printStackTrace(); } return ""; } public static String list2Json(List list) { try { return objectMapper.writeValueAsString(list); } catch (Exception e) { e.printStackTrace(); } return ""; } public static <T> T json2Bean(String json, Class<T> beanClass) { try { return objectMapper.readValue(json, beanClass); } catch (Exception e) { e.printStackTrace(); } return null; } public static <T> List<T> json2List(String json, Class<T> beanClass) { try { return (List<T>)objectMapper.readValue(json, getCollectionType(List.class, beanClass)); } catch (Exception e) { e.printStackTrace(); } return null; } public static Map json2Map(String json) { try { return (Map)objectMapper.readValue(json, Map.class); } catch (Exception e) { e.printStackTrace(); } return null; } public static JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) { return objectMapper.getTypeFactory().constructParametricType(collectionClass, elementClasses); } //------------- @Test public void testBean2Json() throws Exception{ Person person = new Person("张三_testBean2Json", "男", "22"); System.out.println( bean2Json(person) ); // => {"name":"张三_testBean2Json","gender":"男","age":"22"} } @Test public void testMap2Json() throws Exception{ Map<String, String> userMap = new LinkedHashMap<String, String>(); userMap.put("name", "张三_testMap2Json"); userMap.put("gender", "男"); userMap.put("age", "22"); System.out.println( map2Json(userMap) ); // => {"name":"张三_testMap2Json","gender":"男","age":"22"} } @Test public void testList2Json() throws Exception{ List<String> list = new ArrayList<String>(); list.add("张三_testList2Json"); list.add("男"); list.add("22"); System.out.println( list2Json(list) ); // => ["张三_testList2Json","男","22"] List<Person> personList = new ArrayList<Person>(); personList.add( new Person("张1", "男1", "11") ); personList.add( new Person("张2", "男2", "22") ); System.out.println( list2Json(personList) ); // => [{"name":"张1","age":"11","gender":"男1"},{"name":"张2","age":"22","gender":"男2"}] } @Test public void testJson2Bean() throws Exception{ Person person = new Person("张三_testJson2Bean", "男", "22"); String json = bean2Json(person); System.out.println( json2Bean(json, Person.class) ); // => User{ name : "张三_testJson2Bean", gender : "男", age : "22"} json = "{\"name\":\"wahh\"}"; System.out.println( json2Bean(json, Person.class) ); } @Test public void testJson2List() throws Exception{ Person person1 = new Person("张三1", "男1", "11"); Person person2 = new Person("张三2", "男2", "22"); List<Person> personList = new ArrayList<Person>(); personList.add(person1); personList.add(person2); System.out.println( json2List( list2Json(personList) , Person.class) ); // => [User{ name : "张三1", gender : "男1", age : "11"}, User{ name : "张三2", gender : "男2", age : "22"}] } @Test public void testJson2Map() throws Exception{ Person person = new Person("张三", "男", "22"); String json = bean2Json(person); Map map = json2Map(json); System.out.println( map ); // => {name=张三, gender=男, age=22} } }