Object转json字符串，Object转Map，Map转Object 简单源码

发布时间：2020-05-25 16:01:18 所属栏目：Java 来源：互联网

导读：Object转json字符串，Object转Map，Map转Object 简单源码

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public class AppObjectUtil {

private static final Logger logger = LoggerFactory.getLogger(AppObjectUtil.class);
private static final String CLASSNAME = AppObjectUtil.class.getName();
private static final String JSON__PROPERTY_FILE = CLASSNAME;
private static final String ESCAPE_JSON_RESPONSE = "escapeJSONResponse";
private static Boolean iCrossSiteScriptingEnabled = null;
private static Boolean isEscapeNull = false;
private static final String lineSeparator = System.getProperty("line.separator");;
private final static String[][] ESCAPE_CHARACTERS = {
{"\","\\"},
{""","\""},
{"n","\n"},
{"r","\r"},
{"t","\t"},
{"f","\f"},
// 根据http://www.json.org/上说明不必过滤一下字符
//{"'","\'"},
};

private final static String[][] CROSS_SITE_SCRIPTING_CHARACTERS = {
{"&","&"},
{"<","<"},
{">",">"},
};

private static Set<Object> iProcessedObjects;

/**
* <p>Title: </p>
* <p>Description:构造器 </p>
*/
public AppObjectUtil() {
super();
}

/**
* @Title: objectToJson
* @Description: 把对象转换成json格式的数据
* @param object
* @return
*/
public static String toJson(Object object,String dateFormat){
StringBuilder sb=new StringBuilder();
try {
iProcessedObjects = new HashSet<Object>();
outputAsJson(sb,"",object,dateFormat);
} catch (Exception e) {
logger.error("toJson error",e);
}
return sb.toString();
}
public static String toJson(Object object){
StringBuilder sb=new StringBuilder();
try {
iProcessedObjects = new HashSet<Object>();
outputAsJson(sb,object);
} catch (Exception e) {
logger.error("toJson error",e);
}
return sb.toString();
}

/**
* @Title: outputAsJson
* @Description: 返回json格式的数据
* @param sb 返回json数据到StringBuilder对象中
* @param indent 当前indent
* @param object 需要转换成json格式的对象
* @throws Exception
*/
private static void outputAsJson(StringBuilder sb,String indent,Object object,String dateFormat) throws Exception {

if (object == null) {
if(getIsEscapeNull()){
return;
}
sb.append("null");
}else if(object instanceof Date){
Date date=(Date)object;
sb.append(quote(AppDateAndStringUtil.format(date,dateFormat)));
}
else if (iProcessedObjects.contains(object) || object instanceof String ||
object instanceof Character || object instanceof Class || object instanceof Throwable) {
sb.append(quote(object));
}else if (object instanceof Boolean || object instanceof Number) {
sb.append(object.toString());
}else if (object instanceof Map) {
iProcessedObjects.add(object);
Map<?,?> map = (Map<?,?>) object;
if (map.size() == 0) {
sb.append("{}");
}else {
sb.append("{");
Iterator<?> keys = map.keySet().iterator();
int i=0;
while (keys.hasNext()) {
Object key = keys.next();
if(getIsEscapeNull()&&map.get(key)==null){
continue;
}
if(i>0){
sb.append(",");
}
i++;
sb.append(lineSeparator);
sb.append(indent);
sb.append("t");
sb.append(quote(key.toString()));
sb.append(": ");
outputAsJson(sb,indent + "t",map.get(key),dateFormat);
}
sb.append(lineSeparator);
sb.append(indent);
sb.append("}");
}
iProcessedObjects.remove(object);
}else if (object.getClass().isArray()) {
iProcessedObjects.add(object);
int length = Array.getLength(object);
if (length == 0) {
sb.append("[]");
}else if (length == 1) {
sb.append("[");
if(getIsEscapeNull()&&Array.get(object,0)==null){

}else{
outputAsJson(sb,indent,Array.get(object,0),dateFormat);
}
sb.append("]");
}else {
sb.append("[");
int k=0;
for (int i = 0; i < length; i++) {
if(getIsEscapeNull()&&Array.get(object,i)==null){
continue;
}
if (k>0) {
sb.append(",");
}
k++;
sb.append(lineSeparator);
sb.append(indent);
sb.append("t");
outputAsJson(sb,i),dateFormat);
}
sb.append(lineSeparator);
sb.append(indent);
sb.append("t");
sb.append("]");
}
iProcessedObjects.remove(object);
}else if (object instanceof Collection) {
iProcessedObjects.add(object);
outputAsJson(sb,((Collection<?>)object).toArray(),dateFormat);
iProcessedObjects.remove(object);
}else {
iProcessedObjects.add(object);
try {
PropertyDescriptor properties[] = Introspector.getBeanInfo(object.getClass()).getPropertyDescriptors();
Map<Object,Object> map = new HashMap<Object,Object>(properties.length);
for (int i = 0; i < properties.length; i++) {
Method readMethod = properties[i].getReadMethod();
if (readMethod != null) {
boolean isContinue=false;
for(Field field:object.getClass().getDeclaredFields()){
if((field.getName().substring(0,1).toLowerCase()+field.getName().substring(1)).equals(properties[i].getName())){
map.put(field.getName(),readMethod.invoke(object,(Object[])null));
isContinue=true;
break;
}
}
if(!isContinue){
map.put(properties[i].getName(),(Object[])null));
}
}
}
outputAsJson(sb,map,dateFormat);
iProcessedObjects.remove(object);
}catch (InvocationTargetException e) {
logger.error("outputAsJson error",e);
throw e;
}catch (IllegalAccessException e) {
logger.error("IllegalAccessException error",e);
throw e;
}catch (IntrospectionException e) {
logger.error("IntrospectionException error",e);
throw e;
}
}

}
private static void outputAsJson(StringBuilder sb,Object object) throws Exception {
if (object == null) {
if(getIsEscapeNull()){
return;
}
sb.append("null");
}else if (iProcessedObjects.contains(object) || object instanceof String || object instanceof Date ||
object instanceof Character || object instanceof Class || object instanceof Throwable) {
sb.append(quote(object));
}else if (object instanceof Boolean || object instanceof Number) {
sb.append(object.toString());
}else if (object instanceof Map) {
iProcessedObjects.add(object);
Map<?,map.get(key));
}
sb.append(lineSeparator);
sb.append(indent);
sb.append("}");
}
iProcessedObjects.remove(object);
}else if (object.getClass().isArray()) {
iProcessedObjects.add(object);
int length = Array.getLength(object);
if (length == 0) {
sb.append("[]");
}else if (length == 1) {
sb.append("[");
if(getIsEscapeNull()&&Array.get(object,0));
}
sb.append("]");
}else {
sb.append("[");
int k=0;
for (int i = 0; i < length; i++) {
if(getIsEscapeNull()&&Array.get(object,i));
}
sb.append(lineSeparator);
sb.append(indent);
sb.append("t");
sb.append("]");
}
iProcessedObjects.remove(object);
}else if (object instanceof Collection) {
iProcessedObjects.add(object);
outputAsJson(sb,((Collection<?>)object).toArray());
iProcessedObjects.remove(object);
}else {
iProcessedObjects.add(object);
try {
PropertyDescriptor properties[] = Introspector.getBeanInfo(object.getClass()).getPropertyDescriptors();
Map<Object,map);
iProcessedObjects.remove(object);
}catch (InvocationTargetException e) {
logger.error("InvocationTargetException error",e);
throw e;
}
}
}

/**
* @Title: quote
* @Description: 替换掉特殊字符为html识别的字符
* @param object
* @return
*/
private static String quote(Object object) {
String str = object.toString();
for (int i = 0; i < ESCAPE_CHARACTERS.length; i++) {
str = str.replaceAll(ESCAPE_CHARACTERS[i][0],ESCAPE_CHARACTERS[i][1]);
}
if (AppObjectUtil.isCrossSiteScriptingEnabled()) {
for (int i=0; i < CROSS_SITE_SCRIPTING_CHARACTERS.length; i++) {
str = str.replaceAll(CROSS_SITE_SCRIPTING_CHARACTERS[i][0],CROSS_SITE_SCRIPTING_CHARACTERS[i][1]);
}
}
StringBuffer sb = new StringBuffer(str.length() + 2);
sb.append(""");
sb.append(str);
sb.append(""");
String result = sb.toString();
return result;
}

/**
* 这个方法是检查是否支持json对于script的站点跨域问题
* @return true 如果支持json对于script的跨域.
*/
private static boolean isCrossSiteScriptingEnabled() {
if (iCrossSiteScriptingEnabled == null) {
iCrossSiteScriptingEnabled = new Boolean(true);
try {
ResourceBundle bundle = ResourceBundle.getBundle(JSON__PROPERTY_FILE);
String escapeJSONResponse = (String) bundle.getObject(ESCAPE_JSON_RESPONSE);
iCrossSiteScriptingEnabled = new Boolean(escapeJSONResponse);
} catch (MissingResourceException e) {
logger.error("MissingResourceException error",e);
}
}
return iCrossSiteScriptingEnabled.booleanValue();
}

/**
* @Title: sqlStrToSqlQueryString
* @Description: 把sql字符串按行解析并生成合法SQL语句
* @param sqlStr
* @return
* @throws IOException
*/
public static String sqlStrToSqlQueryString(String sqlStr) throws IOException {
if(sqlStr==null){
return null;
}
BufferedReader reader = new BufferedReader(new StringReader(sqlStr));
String line = null;
StringBuffer queryBuffer = null;
while ((line = reader.readLine()) != null) {
if (queryBuffer == null) {
queryBuffer = new StringBuffer();
}
if (line.length() > 0 && !line.startsWith("--")) {
queryBuffer.append(line).append(" ");
if (line.lastIndexOf(";") !=line.length()-1) {
continue;
}else{
return queryBuffer.substring(0,queryBuffer.length()-2);
}
}
}
if(queryBuffer==null){
return sqlStr;
}
return queryBuffer.substring(0,queryBuffer.length()-1);
}

/**
* @return the isEscapeNull
*/
public static Boolean getIsEscapeNull() {
return isEscapeNull;
}

/**
* @param isEscapeNull the isEscapeNull to set
*/
public static void setIsEscapeNull(Boolean isEscapeNull) {
AppObjectUtil.isEscapeNull = isEscapeNull;
}
/**
* @Title: generateFieldMapFromObject
* @param targetClass
* @return
* @throws Exception
*/
public static Map<String,Object> generateFieldMapFromObject(Object targetClass)throws Exception{
if (targetClass == null) {
return null;
}
Map<String,Object> fieldMap=null;
PropertyDescriptor properties[] = Introspector.getBeanInfo(targetClass.getClass()).getPropertyDescriptors();
for (int i = 0; i < properties.length; i++) {
Method readMethod = properties[i].getReadMethod();
if (readMethod != null) {
if(fieldMap==null){
fieldMap=new HashMap<String,Object>();
}
boolean isContinue=false;
for(Field field:targetClass.getClass().getDeclaredFields()){
if((field.getName().substring(0,1).toLowerCase()+field.getName().substring(1)).equals(properties[i].getName())){
fieldMap.put(field.getName(),readMethod.invoke(targetClass,(Object[])null));
isContinue=true;
break;
}
}
if(!isContinue){
try {
fieldMap.put(properties[i].getName(),readMethod.invoke(targetClass.getClass(),(Object[])null));
} catch (Exception e) {
}
}
}
}
return fieldMap;

}
/**
* @param targetClass
* @param fieldMap
* @return
* @throws Exception
*/
public static Object generateObjectFromFieldMap(Object targetClass,Map<String,Object> fieldMap) throws Exception {
if (targetClass == null) {
return null;
}
Class<?> objectClass = null;
if (targetClass instanceof Class) {
objectClass = (Class<?>) targetClass;
targetClass = objectClass.newInstance();
} else {
objectClass = targetClass.getClass();
}
PropertyDescriptor properties[] = Introspector.getBeanInfo(objectClass).getPropertyDescriptors();
for (int i = 0; i < properties.length; i++) {
Method writeMethod = properties[i].getWriteMethod();
if (writeMethod != null) {
Object value=null;
for(Field field:objectClass.getDeclaredFields()){
if((field.getName().substring(0,1).toLowerCase()+field.getName().substring(1)).equals(properties[i].getName())){
value=fieldMap.get(field.getName());
break;
}
}
if(value==null){
value=fieldMap.get(properties[i].getName());
}
if(value==null){
for (Map.Entry<String,Object> entry : fieldMap.entrySet()) {
if (entry.getValue() != null) {
String setMethodName = "set" + entry.getKey().substring(0,1).toUpperCase()+ entry.getKey().substring(1);
if(writeMethod.getName().equals(setMethodName)){
value=entry.getValue();
}
}
}
}
if(value!=null&&(!"".equals(value.toString().trim()))){
for(Class<?> c:writeMethod.getParameterTypes()){
if("java.lang.Integer".equals(c.getName())||"int".equals(c.getName())){
writeMethod.invoke(targetClass,Integer.valueOf(value.toString()));
break;
}
if("java.lang.Long".equals(c.getName())||"long".equals(c.getName())){
writeMethod.invoke(targetClass,Long.valueOf(value.toString()));
break;
}
if("java.lang.Double".equals(c.getName())||"double".equals(c.getName())){
writeMethod.invoke(targetClass,Double.valueOf(value.toString()));
break;
}
if("java.lang.Float".equals(c.getName())||"float".equals(c.getName())){
writeMethod.invoke(targetClass,Float.valueOf(value.toString()));
break;
}
if("java.lang.String".equals(c.getName())){
writeMethod.invoke(targetClass,value.toString());
break;
}
if("java.math.BigDecimal".equals(c.getName())){
writeMethod.invoke(targetClass,new BigDecimal(value.toString().replaceAll(",","")));
break;
}
if("java.util.Date".equals(c.getName())&&"java.lang.String".equals(value.getClass().getName())){
String df = "yyyy-MM-dd";
if(value.toString().length()>10){
df = "yyyy-MM-dd HH:mm:ss";
}
writeMethod.invoke(targetClass,AppDateAndStringUtil.parse(value.toString(),df));
break;
}
try {
writeMethod.invoke(targetClass,value);
} catch (Exception e) {
logger.error("generateObjectFromFieldMap error",e);
}
break;
}
}
}
}
return targetClass;
}
}

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