json：java对象与json字符串互转、java的list和map各自与json字符串的互转

来源：互联网发布：英雄联盟关注软件编辑：程序博客网时间：2024/05/30 05:41

import java.io.StringReader;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import antlr.RecognitionException;
import antlr.TokenStreamException;
import com.sdicons.json.mapper.JSONMapper;
import com.sdicons.json.mapper.MapperException;
import com.sdicons.json.model.JSONArray;
import com.sdicons.json.model.JSONValue;
import com.sdicons.json.parser.JSONParser;
public class JsonUtil {
/**
* JAVA对象转换成JSON字符串
* @param obj
* @return
* @throws MapperException
*/
public static String objectToJsonStr(Object obj) throws MapperException{
JSONValue jsonValue = JSONMapper.toJSON(obj);
String jsonStr = jsonValue.render(false);
return jsonStr;
}
/**
* 重载objectToJsonStr方法
* @param obj 需要转换的JAVA对象
* @param format 是否格式化
* @return
* @throws MapperException
*/
public static String objectToJsonStr(Object obj,boolean format) throws MapperException{
JSONValue jsonValue = JSONMapper.toJSON(obj);
String jsonStr = jsonValue.render(format);
return jsonStr;
}
/**
* JSON字符串转换成JAVA对象
* @param jsonStr
* @param cla
* @return
* @throws MapperException
* @throws TokenStreamException
* @throws RecognitionException
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public static Object jsonStrToObject(String jsonStr,Class<?> cla) throws MapperException, TokenStreamException, RecognitionException{
Object obj = null;
try{
JSONParser parser = new JSONParser(new StringReader(jsonStr));
JSONValue jsonValue = parser.nextValue();
if(jsonValue instanceof com.sdicons.json.model.JSONArray){
List list = new ArrayList();
JSONArray jsonArray = (JSONArray) jsonValue;
for(int i=0;i<jsonArray.size();i++){
JSONValue jsonObj = jsonArray.get(i);
Object javaObj = JSONMapper.toJava(jsonObj,cla);
list.add(javaObj);
}
obj = list;
}else if(jsonValue instanceof com.sdicons.json.model.JSONObject){
obj = JSONMapper.toJava(jsonValue,cla);
}else{
obj = jsonValue;
}
}catch(Exception e){
e.printStackTrace();
}
return obj;
}
/**
* 将JAVA对象转换成JSON字符串
* @param obj
* @return
* @throws IllegalArgumentException
* @throws IllegalAccessException
*/
@SuppressWarnings("rawtypes")
public static String simpleObjectToJsonStr(Object obj,List<Class> claList) throws IllegalArgumentException, IllegalAccessException{
if(obj==null){
return "null";
}
String jsonStr = "{";
Class<?> cla = obj.getClass();
Field fields[] = cla.getDeclaredFields();
for (Field field : fields) {
field.setAccessible(true);
if(field.getType() == long.class){
jsonStr += "\""+field.getName()+"\":"+field.getLong(obj)+",";
}else if(field.getType() == double.class){
jsonStr += "\""+field.getName()+"\":"+field.getDouble(obj)+",";
}else if(field.getType() == float.class){
jsonStr += "\""+field.getName()+"\":"+field.getFloat(obj)+",";
}else if(field.getType() == int.class){
jsonStr += "\""+field.getName()+"\":"+field.getInt(obj)+",";
}else if(field.getType() == boolean.class){
jsonStr += "\""+field.getName()+"\":"+field.getBoolean(obj)+",";
}else if(field.getType() == Integer.class||field.getType() == Boolean.class
||field.getType() == Double.class||field.getType() == Float.class
||field.getType() == Long.class){
jsonStr += "\""+field.getName()+"\":"+field.get(obj)+",";
}else if(field.getType() == String.class){
jsonStr += "\""+field.getName()+"\":\""+field.get(obj)+"\",";
}else if(field.getType() == List.class){
String value = simpleListToJsonStr((List<?>)field.get(obj),claList);
jsonStr += "\""+field.getName()+"\":"+value+",";
}else{
if(claList!=null&&claList.size()!=0&&claList.contains(field.getType())){
String value = simpleObjectToJsonStr(field.get(obj),claList);
jsonStr += "\""+field.getName()+"\":"+value+",";
}else{
jsonStr += "\""+field.getName()+"\":null,";
}
}
}
jsonStr = jsonStr.substring(0,jsonStr.length()-1);
jsonStr += "}";
return jsonStr;
}
/**
* 将JAVA的LIST转换成JSON字符串
* @param list
* @return
* @throws IllegalArgumentException
* @throws IllegalAccessException
*/
@SuppressWarnings("rawtypes")
public static String simpleListToJsonStr(List<?> list,List<Class> claList) throws IllegalArgumentException, IllegalAccessException{
if(list==null||list.size()==0){
return "[]";
}
String jsonStr = "[";
for (Object object : list) {
jsonStr += simpleObjectToJsonStr(object,claList)+",";
}
jsonStr = jsonStr.substring(0,jsonStr.length()-1);
jsonStr += "]";
return jsonStr;
}
/**
* 将JAVA的MAP转换成JSON字符串，
* 只转换第一层数据
* @param map
* @return
*/
public static String simpleMapToJsonStr(Map<?,?> map){
if(map==null||map.isEmpty()){
return "null";
}
String jsonStr = "{";
Set<?> keySet = map.keySet();
for (Object key : keySet) {
jsonStr += "\""+key+"\":\""+map.get(key)+"\",";
}
jsonStr = jsonStr.substring(0,jsonStr.length()-1);
jsonStr += "}";
return jsonStr;
}
}

注意：实际运行程序时需导入包jsontools-core-1.7.jar

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