Java web 開發中幾個高可複用的類

標籤：exce   val   string   class   for   classes   json   log   lse   

1. JsonUtil

　　通過  jackson包提供的方法 實現一個字串轉對象,對象轉字串的類,使用情境,redis實現單點登陸 

package com.mmall.util;import com.google.common.collect.Lists;import com.mmall.pojo.Category;import com.mmall.pojo.TestPojo;import com.mmall.pojo.User;import lombok.extern.slf4j.Slf4j;import org.apache.commons.lang.StringUtils;import org.codehaus.jackson.map.DeserializationConfig;import org.codehaus.jackson.map.ObjectMapper;import org.codehaus.jackson.map.SerializationConfig;import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;import org.codehaus.jackson.type.JavaType;import org.codehaus.jackson.type.TypeReference;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.HashMap;import java.util.List;import java.util.Map;/** * Created by geely */@Slf4jpublic class JsonUtil {    private static ObjectMapper objectMapper = new ObjectMapper();    static{        //對象的所有欄位全部列入        objectMapper.setSerializationInclusion(Inclusion.ALWAYS);        //取消預設轉換timestamps形式        objectMapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS,false);        //忽略空Bean轉json的錯誤        objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS,false);        //所有的日期格式都統一為以下的樣式，即yyyy-MM-dd HH:mm:ss        objectMapper.setDateFormat(new SimpleDateFormat(DateTimeUtil.STANDARD_FORMAT));        //忽略 在json字串中存在，但是在java對象中不存在對應屬性的情況。防止錯誤        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false);    }    public static <T> String obj2String(T obj){        if(obj == null){            return null;        }        try {            return obj instanceof String ? (String)obj :  objectMapper.writeValueAsString(obj);        } catch (Exception e) {            log.warn("Parse Object to String error",e);            return null;        }    }    public static <T> String obj2StringPretty(T obj){        if(obj == null){            return null;        }        try {            return obj instanceof String ? (String)obj :  objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);        } catch (Exception e) {            log.warn("Parse Object to String error",e);            return null;        }    }    public static <T> T string2Obj(String str,Class<T> clazz){        if(StringUtils.isEmpty(str) || clazz == null){            return null;        }        try {            return clazz.equals(String.class)? (T)str : objectMapper.readValue(str,clazz);        } catch (Exception e) {            log.warn("Parse String to Object error",e);            return null;        }    }    public static <T> T string2Obj(String str, TypeReference<T> typeReference){        if(StringUtils.isEmpty(str) || typeReference == null){            return null;        }        try {            return (T)(typeReference.getType().equals(String.class)? str : objectMapper.readValue(str,typeReference));        } catch (Exception e) {            log.warn("Parse String to Object error",e);            return null;        }    }    public static <T> T string2Obj(String str,Class<?> collectionClass,Class<?>... elementClasses){        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass,elementClasses);        try {            return objectMapper.readValue(str,javaType);        } catch (Exception e) {            log.warn("Parse String to Object error",e);            return null;        }    }}

 

Java web 開發中幾個高可複用的類