原文：总结的一些json格式和对象/String/Map/List等的互转工具类
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总结的一些json格式和对象/String/Map/List等的互转工具类，有需要的可以看看,需要引入jackson-core-asl-1.7.1.jar、jackson-jaxrs-1.7.1.jar、jackson-mapper-asl-1.7.1.jar这三个jar包
package com.zuidaima.util.json;import java.io.InputStream;import java.io.OutputStream;import java.io.Reader;import java.io.Writer;import java.net.URL;import java.util.ArrayList;import java.util.Date;import java.util.HashMap;import java.util.List;import java.util.Map;import org.codehaus.jackson.JsonNode;import org.codehaus.jackson.map.DeserializationConfig;import org.codehaus.jackson.map.ObjectMapper;import org.codehaus.jackson.map.annotate.JsonSerialize;import org.codehaus.jackson.map.type.TypeFactory;public class JsonUtil {private static ObjectMapper mapper = new ObjectMapper();static{/** * 反序列化时忽略多余的属性 */mapper.getDeserializationConfig().set(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);/** * 忽略Null的值,节省空间.* @author */mapper.getSerializationConfig().setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);/*** 忽略Default值木有变化的属性,更节省空间,用于接收方有相同的Class* 如int属性初始值为0,那么这个属性将不会被序列化*/mapper.getSerializationConfig().setSerializationInclusion(JsonSerialize.Inclusion.NON_DEFAULT);}/** * * @Title: isJSON * @author kaka* @Description: 判断 jsonString是否可以转换成json格式 * @param @param jsonString * @param @return* @return boolean* @throws */public static boolean isJSON(String jsonString) {return mapper.canSerialize(HashMap.class);}public static <V> Map<String, V> toMap(String content,Class<? extends V> clazz) throws Exception {return mapper.readValue(content, TypeFactory.mapType(HashMap.class,String.class, clazz));}public static <V> Map<String, V> toMap(InputStream is,Class<? extends V> clazz) throws Exception {return mapper.readValue(is, TypeFactory.mapType(HashMap.class,String.class, clazz));}public static <V> Map<String, V> toMap(Reader is, Class<? extends V> clazz)throws Exception {return mapper.readValue(is, TypeFactory.mapType(HashMap.class,String.class, clazz));}public static <V> Map<String, V> toMap(URL is, Class<? extends V> clazz)throws Exception {return mapper.readValue(is, TypeFactory.mapType(HashMap.class,String.class, clazz));}public static <E> List<E> toList(String content, Class<? extends E> clazz)throws Exception {return jsonToList(content, clazz);}/** * * @Title: jsonToList * @author kaka* @Description: json转list , List的元素类型，会一并转换完成 如List<User> * @param @param <E> * @param @param content * @param @param clazz * @param @return 元素类型为E的List * @param @throws Exception* @return List<E>* @throws */public static <E> List<E> jsonToList(String content,Class<? extends E> clazz) throws Exception {return mapper.readValue(content, TypeFactory.collectionType(ArrayList.class, clazz));}/** * * @Title: jsonToIntArray * @author kaka* @Description: json转整形数组 * @param @param content * @param @return * @param @throws Exception* @return Integer[]* @throws */public static Integer[] jsonToIntArray(String content) throws Exception {return jsonToArray(content, Integer.class);}public static Integer[] jsonToIntArray(String content,String key) throws Exception {return jsonToArray(content, key, Integer.class);}/** * * @Title: jsonToArray * @author kaka* @Description: json转对象数组* @param @param <E> * @param @param content * @param @param clazz 数组中的对象类型 * @param @return E类型的数组，如User[] * @param @throws Exception* @return E[]* @throws */public static <E> E[] jsonToArray(String content, Class<? extends E> clazz)throws Exception {if(content != null){return mapper.readValue(content, TypeFactory.arrayType(clazz));}else{return null;}}/** * * @Title: fromJsonToObject * @author kaka* @Description: json转java对象，，为兼容原util类 * @param @param <T> * @param @param content * @param @param clazz 目标类型 * @param @return * @param @throws Exception* @return T 返回类型为T的对象 * @throws */public static <T> T fromJsonToObject(String content,Class<? extends T> clazz) throws Exception {return jsonToObject(content, clazz);}public static <T> T jsonToObject(String content, Class<? extends T> clazz)throws Exception {return mapper.readValue(content, clazz);}/** * * @Title: jsonToObject * @author kaka* @Description: 一个jsonStr包含多个java对象，取其中一个转化为java对象的方法* @param @param <T> * @param @param content json格式的字符串 * @param @param key 要转换的子json串的key * @param @param clazz 目标类型 * @param @return 返回类型为T的对象 * @param @throws Exception* @return T* @throws */public static <T> T jsonToObject(String content, String key,Class<? extends T> clazz) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return jsonToObject(path.toString(), clazz);}else{return null;}}public static Integer getInt(String content, String key) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return jsonToObject(path.toString(), Integer.class);}else{return null;}}public static String getString(String content, String key) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return jsonToObject(rootNode.path(key).toString(), String.class);}else{return null;}}public static Date getDate(String content, String key) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return jsonToObject(path.toString(), Date.class);}else{return null;}}/** * 一个jsonStr包含多个java对象，将指定的key的json转化为对象数组的方法 * @param content 原始的json串 * @param key 要转换的部分 * @param clazz 目标类型 * @return 目标类型的对象数组 * @throws Exception */public static <E> E[] jsonToArray(String content, String key,Class<? extends E> clazz) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return jsonToArray(rootNode.path(key).toString(), clazz);}else{return null;}}public static Integer[] jsonToArray(String content, String key) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return jsonToArray(path.toString(), Integer.class);}else{return null;}}/** * * @Title: jsonToList * @author kaka* @Description: 一个jsonStr包含多个java对象，将指定的key的json转化为List<E>的方法 * @param @param <E> * @param @param content 原始的json串 * @param @param key 要转换的那部分json * @param @param clazz 目标类型 * @param @return 元素为目标类型的List * @param @throws Exception* @return List<E>* @throws */public static <E> List<E> jsonToList(String content, String key,Class<? extends E> clazz) throws Exception {JsonNode rootNode = mapper.readValue(content, JsonNode.class);JsonNode path = rootNode.path(key);if(!path.isMissingNode()){return toList(path.toString(), clazz);}else{return null;}}/** * * @Title: toJson * @author kaka* @Description: 对象转化成json，已知问题 A a B b b中有a，a中有b ， 如果a和b同在一个o中将不能正常转化* @param @param o 要转换的对象 * @param @return json格式的字符串 * @param @throws Exception* @return String* @throws */public static String toJson(Object o) throws Exception {return mapper.writeValueAsString(o);}/** * * @Title: toJson * @author kaka* @Description: 转换成json串到out* @param @param out * @param @param o * @param @throws Exception* @return void* @throws */public static void toJson(OutputStream out, Object o) throws Exception {mapper.writeValue(out, o);}/** * * @Title: toJson * @author kaka* @Description: 转换成json串到writer* @param @param out * @param @param o * @param @throws Exception* @return void* @throws */public static void toJson(Writer out, Object o) throws Exception {mapper.writeValue(out, o);}public static String map2Json(Map map) throws Exception{return toJson(map);}/** * * @Title: formatJson * @author kaka* @Description: json字符串的格式化* @param @param json * @param @param fillStringUnit * @param @return* @return String* @throws */public static String formatJson(String json, String fillStringUnit) {if (json == null || json.trim().length() == 0) {return null;}int fixedLenth = 0;ArrayList<String> tokenList = new ArrayList<String>();{String jsonTemp = json;//预读取while (jsonTemp.length() > 0) {String token = getToken(jsonTemp);jsonTemp = jsonTemp.substring(token.length());token = token.trim();tokenList.add(token);}}for (int i = 0; i < tokenList.size(); i++) {String token = tokenList.get(i);int length = token.getBytes().length;if (length > fixedLenth && i < tokenList.size() – 1 && tokenList.get(i + 1).equals(":")) {fixedLenth = length;}}StringBuilder buf = new StringBuilder();int count = 0;for (int i = 0; i < tokenList.size(); i++) {String token = tokenList.get(i);if (token.equals(",")) {buf.append(token);doFill(buf, count, fillStringUnit);continue;}if (token.equals(":")) {buf.append(" ").append(token).append(" ");continue;}if (token.equals("{")) {String nextToken = tokenList.get(i + 1);if (nextToken.equals("}")) {i++;buf.append("{ }");} else {count++;buf.append(token);doFill(buf, count, fillStringUnit);}continue;}if (token.equals("}")) {count–;doFill(buf, count, fillStringUnit);buf.append(token);continue;}if (token.equals("[")) {String nextToken = tokenList.get(i + 1);if (nextToken.equals("]")) {i++;buf.append("[ ]");} else {count++;buf.append(token);doFill(buf, count, fillStringUnit);}continue;}if (token.equals("]")) {count–;doFill(buf, count, fillStringUnit);buf.append(token);continue;}buf.append(token);//左对齐if (i < tokenList.size() – 1 && tokenList.get(i + 1).equals(":")) {int fillLength = fixedLenth – token.getBytes().length;if (fillLength > 0) {for(int j = 0; j < fillLength; j++) {buf.append(" ");}}}}return buf.toString();}private static String getToken(String json) {StringBuilder buf = new StringBuilder();boolean isInYinHao = false;while (json.length() > 0) {String token = json.substring(0, 1);json = json.substring(1);if (!isInYinHao &&(token.equals(":") || token.equals("{") || token.equals("}")|| token.equals("[") || token.equals("]")|| token.equals(","))) {if (buf.toString().trim().length() == 0) {buf.append(token);}break;}if (token.equals("\\")) {buf.append(token);buf.append(json.substring(0, 1));json = json.substring(1);continue;}if (token.equals("\&;")) {buf.append(token);if (isInYinHao) {break;} else {isInYinHao = true;continue;}}buf.append(token);}return buf.toString();}private static void doFill(StringBuilder buf, int count, String fillStringUnit) {buf.append("\n");for (int i = 0; i < count; i++) {buf.append(fillStringUnit);}}}
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