Json使用 jackjson 工具类
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.type.JavaType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class JsonUtil {
private static ObjectMapper objectMapper = new ObjectMapper();
private static JsonGenerator jsonGenerator = JsonUtil.getJsonGenerator();
private static Logger log = LoggerFactory.getLogger(JsonUtil.class);
private static JsonGenerator getJsonGenerator() {
try {
jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(System.out, JsonEncoding.UTF8);
return jsonGenerator;
} catch (IOException e) {
log.error("get JsonGenerator error!" + e.toString());
return null;
}
}
/**
* 把Java对象转换成json串
*
* @throws IOException
*/
public static String writeEntity2Json(Object object) throws IOException {
if (null == object) {
log.error("class:JsonUtil,method:writeEntity2Json,param:object == null");
return null;
}
log.debug("class:JsonUtil,method:writeEntity2Json,param:object=" + object);
return objectMapper.writeValueAsString(object);
}
/**
* 把List转换成json串
*
* @param list
* @return
* @throws IOException
*/
@SuppressWarnings("rawtypes")
public static String writeList2Json(List list) throws IOException {
return objectMapper.writeValueAsString(list);
}
/**
* 把List<Object>转换成List<json串>
*
* @param list
* @return
* @throws IOException
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public static List<String> writeListObject2Json(List list) throws IOException {
List<String> objectList = new ArrayList();
Iterator iter = list.iterator();
while (iter.hasNext()) {
Object o = iter.next();
String json = objectMapper.writeValueAsString(o);
objectList.add(json);
}
return objectList;
}
/**
* 把List<Object>转换成String[json串]
*
* @param list
* @return
* @throws IOException
*/
@SuppressWarnings("rawtypes")
public static String[] writeListObject2ArrayJson(List list) throws IOException {
if (null == list || list.size() == 0) {
log.error("class:JsonUtil,method:writeListObject2ArrayJson,param==null");
return null;
}
String[] arrayJson = new String[list.size()];
for (int i = 0; i < list.size(); i++) {
Object o = list.get(i);
String json = objectMapper.writeValueAsString(o);
arrayJson[i] = json;
}
return arrayJson;
}
/**
* 把map转换成json串
*
* @param map
* @return
*/
@SuppressWarnings("rawtypes")
public static String writeMap2Json(Map map) {
try {
return objectMapper.writeValueAsString(map);
} catch (JsonGenerationException e) {
e.printStackTrace();
return null;
} catch (JsonMappingException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* JSON字符串转换为对象
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public static Object readJson2Entity(String json, Class c) {
log.debug("class:JsonUtil,method:readJson2Entity,param:json=" + json);
try {
return objectMapper.readValue(json, c);
} catch (JsonParseException e) {
log.error("class:JsonUtil,method:readJson2Entity", e);
return null;
} catch (JsonMappingException e) {
log.error("class:JsonUtil,method:readJson2Entity", e);
return null;
} catch (IOException e) {
log.error("class:JsonUtil,method:readJson2Entity", e);
return null;
}
}
/**
* JSON转换为List对象
*/
@SuppressWarnings("unchecked")
public static List<LinkedHashMap<String, Object>> readJson2List(String json) {
try {
return objectMapper.readValue(json, List.class);
} catch (JsonParseException e) {
e.printStackTrace();
return null;
} catch (JsonMappingException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* JSON转换为数组对象
*/
public static Object[] readJson2Array(String json) {
try {
return objectMapper.readValue(json, Object[].class);
} catch (JsonParseException e) {
e.printStackTrace();
return null;
} catch (JsonMappingException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* JSON转换为Map对象
*/
@SuppressWarnings("unchecked")
public static Map<String, Map<String, Object>> readJson2Map(String json) {
try {
return objectMapper.readValue(json, Map.class);
} catch (JsonParseException e) {
e.printStackTrace();
return null;
} catch (JsonMappingException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* 对象转换字符串
*
* @param obj
* @return
*/
public static String Object2String(Object obj) {
String result = null;
try {
result = objectMapper.writeValueAsString(obj);
} catch (Exception e) {
log.error("json转换异常", e);
}
return result;
}
/**
* 字符串转换对象
*
* @param json
* @param classObj
* @return
*/
public static Object String2Object(String json, Class<?> classObj) {
Object result = null;
try {
result = objectMapper.readValue(json, classObj);
} catch (Exception e) {
log.error("json转换异常", e);
}
return result;
}
/**
* 字符串转换Pagination对象,此类有firstIndex":1,"lastIndex":1属性会导致转换异常，过滤这2个属性
*
* @param json
* @param classObj
* @return
*/
public static Object String2Pagination(String json, Class<?> classObj) {
Object result = null;
try {
ObjectMapper objectMapper = new ObjectMapper();
// 设置输入时忽略在JSON字符串中存在但Java对象实际没有的属性
objectMapper.disable(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES);
result = objectMapper.readValue(json, classObj);
} catch (Exception e) {
log.error("json转换异常", e);
}
return result;
}
/**
* 字符串转换为List<?>
*
* @param json
* @param classObj
* @return
*/
public static Object String2List(String json, Class<?> classObj) {
Object result = null;
try {
result = objectMapper.readValue(json, getCollectionType(ArrayList.class, classObj));
} catch (Exception e) {
log.error("json转换异常", e);
}
return result;
}
private static JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
return objectMapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
}
}
//json工具类泛型接口
import java.util.ArrayList;
import java.util.List;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.type.JavaType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
*
*/
public class JsonUtil {
private static final Logger logger = LoggerFactory.getLogger(JsonUtil.class);
private static ObjectMapper mapper = new ObjectMapper();
/**
* 对象转换字符串
*
* @param obj
* @return
*/
public static String Object2String(Object obj) {
String result = null;
try {
result = mapper.writeValueAsString(obj);
} catch (Exception e) {
logger.error("json转换异常", e);
}
return result;
}
/**
* 字符串转换对象
*
* @param json
* @param classObj
* @return
* @return
*/
public static <T> T String2Object(String json, Class<T> classObj) {
T result = null;
try {
result = mapper.readValue(json, classObj);
} catch (Exception e) {
logger.error("json转换异常", e);
}
return result;
}
/**
* 字符串转换成较复杂的对象，如泛型对象
*
* @param json
* @param classObj
* @param valueType
* @return
*/
public static <T> T String2Object(String json, Class<?> classObj, Class<?>... valueType) {
T result = null;
try {
result = mapper.readValue(json, getCollectionType(classObj, valueType));
} catch (Exception e) {
logger.error("json转换异常", e);
}
return result;
}
/**
* 字符串转换为List<T>
*
* @param json
* @param classObj
* @return
*/
public static <T> List<T> String2List(String json, Class<T> classObj) {
List<T> result = null;
try {
result = mapper.readValue(json, getCollectionType(ArrayList.class, classObj));
} catch (Exception e) {
logger.error("json转换异常", e);
}
return result;
}
private static JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
return mapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
}
}
原文链接：https://blog.csdn.net/hjxgood/article/details/20127319 标签：return,json,Json,jackjson,static,result,catch,工具,null From： https://www.cnblogs.com/sunny3158/p/18555172