Java分页、Json工具类
1.JSON数据转换工具类
import java.util.List; import java.util.Map; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.reflect.TypeToken; /** * JSON数据互转工具类 */ public class JsonUtils { static Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create(); /** 将list转化为json字符串 */ public static String list2json(List<?> list) { if(list==null) return "[]"; String str = gson.toJson(list); return str; } /** 将对象转化为json字符串(类 或者 Map) */ public static String obj2json(Object obj) { if(obj==null) return "{}"; String str = gson.toJson(obj); return str; } /** 将json字符串转化为List<String> */ public static List<String> json2list(String jsonStr) { try{ List<String> list = gson.fromJson(jsonStr, new TypeToken<List<String>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为List<Integer> */ public static List<Integer> json2listInt(String jsonStr) { try{ List<Integer> list = gson.fromJson(jsonStr, new TypeToken<List<Integer>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为List<Map<Object,Object>> */ public static List<Map<Object,Object>> json2listMap(String jsonStr) { try{ List<Map<Object,Object>> list = gson.fromJson(jsonStr, new TypeToken<List<Map<Object,Object>>>() { }.getType()); return list; }catch(Exception e){ e.printStackTrace(); } return null; } /** 将json字符串转化为List<Map<String,Object>> */ public static List<Map<String,Object>> json2listMapStrObj(String jsonStr) { try{ List<Map<String,Object>> list = gson.fromJson(jsonStr, new TypeToken<List<Map<String,Object>>>() { }.getType()); return list; }catch(Exception e){ e.printStackTrace(); } return null; } /** 将json字符串转化为List<Map<String,String>> */ public static List<Map<String,String>> json2listMapStr(String jsonStr) { try{ List<Map<String,String>> list = gson.fromJson(jsonStr, new TypeToken<List<Map<String,String>>>() { }.getType()); return list; }catch(Exception e){ e.printStackTrace(); } return null; } /** 将json字符串转化为List<Object> */ public static List<Object> json2listObj(String jsonStr) { try{ List<Object> list = gson.fromJson(jsonStr, new TypeToken<List<Object>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为List<List<String> */ public static List<List<String>> json2list2String(String jsonStr) { try{ List<List<String>> list = gson.fromJson(jsonStr, new TypeToken<List<List<String>>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,Object> */ public static Map<String,Object> json2Map(String jsonStr) { try{ Map<String,Object> map = gson.fromJson(jsonStr, new TypeToken<Map<String,Object>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,String> */ public static Map<String,String> json2MapSingleStr(String jsonStr) { try{ Map<String,String> map = gson.fromJson(jsonStr, new TypeToken<Map<String,String>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,Double> */ public static Map<String,Double> json2MapSingleDou(String jsonStr) { try{ Map<String,Double> map = gson.fromJson(jsonStr, new TypeToken<Map<String,Double>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,Map<String,String>> */ public static Map<String,Map<String,String>> json2MapInMapStr(String jsonStr) { try{ Map<String,Map<String,String>> map = gson.fromJson(jsonStr, new TypeToken<Map<String,Map<String,String>>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,Map<String,Float>> */ public static Map<String,Map<String,Float>> json2MapInMapFloat(String jsonStr) { try{ Map<String,Map<String,Float>> map = gson.fromJson(jsonStr, new TypeToken<Map<String,Map<String,Float>>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,List<Integer> */ public static Map<String,List<Integer>> json2MapInListInt(String jsonStr) { try{ Map<String,List<Integer>> map = gson.fromJson(jsonStr, new TypeToken<Map<String,List<Integer>>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,List<String> */ public static Map<String,List<String>> json2MapInListString(String jsonStr) { try{ Map<String,List<String>> map = gson.fromJson(jsonStr, new TypeToken<Map<String,List<String>>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,List<List<String>> */ public static Map<String,List<List<String>>> json2MapInListStringListString(String jsonStr) { try{ Map<String,List<List<String>>> map = gson.fromJson(jsonStr, new TypeToken<Map<String,List<List<String>>>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为Map<String,List<Integer> */ public static Map<Integer,List<Integer>> json2MapInListInt_int(String jsonStr) { try{ Map<Integer,List<Integer>> map = gson.fromJson(jsonStr, new TypeToken<Map<Integer,List<Integer>>>() { }.getType()); return map; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为List<String[]> */ public static List<String[]> json2ListStrArr(String jsonStr) { try{ List<String[]> list = gson.fromJson(jsonStr, new TypeToken<List<String[]>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为List<Float[]> */ public static List<Float[]> json2ListFloatArr(String jsonStr) { try{ List<Float[]> list = gson.fromJson(jsonStr, new TypeToken<List<Float[]>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为List<Float> */ public static List<Float> json2ListFloat(String jsonStr) { try{ List<Float> list = gson.fromJson(jsonStr, new TypeToken<List<Float>>() { }.getType()); return list; }catch(Exception e){ //e.printStackTrace(); } return null; } /** 将json字符串转化为AjaxDto */ /*public static AjaxDto json2AjaxDto(String jsonStr) { AjaxDto map = gson.fromJson(jsonStr, new TypeToken<AjaxDto>() { }.getType()); return map; }*/ }
注：需要引入cosn.jar包。
2.分页工具类
/**分页工具类 */ public class Pager<T> { /** 换数据类型时使用 */ public Pager(Pager<?> pager,List<?> datas){ this.currPage=pager.currPage; this.pages=pager.pages; this.pageSize=pager.pageSize; this.count=pager.count; this.ind=pager.ind; this.datas=(List<T>)datas; } public Pager(int currPage){ this.currPage=currPage<1?1:currPage; } public Pager(int currPage,int pageSize){ this.currPage=currPage<1?1:currPage; this.pageSize=pageSize; } private int currPage;//当前页 设置-100时，则不分页和获取页数(只在有需要的地方加此逻辑) private int pages;//总页数 private int pageSize=10;//每页条数 private int count;//总条数 private int ind; private List<T> datas; private Object other; public Pager<T> setData(int count,List<T> datas){ this.setCount(count); this.datas=datas; return this; } /** 不能确认每页条数才使用 */ public Pager<T> setDataLikeCount(int pages,List<T> datas){ this.pages=pages; this.datas=datas; return this; } public List<T> getData(){ return this.datas; } private void setCount(int count) { this.count = count; this.ind = ((currPage-1)*pageSize)+1; this.pages = count==0?1:((int)(count/pageSize+(count%pageSize==0?0:1))); } public int getCount(){ return count; } /** 获取每页条数 */ public int getPageSize(){ return this.pageSize; } public int getStartCount(){ return (currPage - 1) * pageSize; } public Object getOther() { return other; } public void setOther(Object other) { this.other = other; } public String toJson(){ return JsonUtils.obj2json(this); } public static Pager<Object> getBlankDatas(){ Pager<Object> pager = new Pager<Object>(1); pager.setData(0,new ArrayList<Object>(0)); return pager; } }
注：该类中引用了JSON数据转换工具类，可以改成自己需要的，也可以删除。
3.接口返回工具类
public class AjaxDto { public AjaxDto(){} public AjaxDto(int result){ this.result=result; } public AjaxDto(int result, String msg, Object obj) { this.result = result; this.msg = msg; this.obj = obj; } public AjaxDto(int result, String msg) { this.result = result; this.msg = msg; } public AjaxDto(int result, String msg,HttpServletRequest request) { this.result = result; this.msg = msg; this.request=request; } public AjaxDto(int result, String msg, Object obj,HttpServletRequest request) { this.result = result; this.msg = msg; this.obj = obj; this.request=request; } /** * 0表示失败 1表示成功 */ private int result; /** * 提示信息 */ private String msg; /** * 附加对象，用来存储一些特定的返回信息 */ protected Object obj; private transient HttpServletRequest request; public int getResult() { return result; } public void setResult(int result) { this.result = result; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } public Object getObj() { return obj; } public void setObj(Object obj) { this.obj = obj; } public HttpServletRequest getRequest() { return request; } public void setRequest(HttpServletRequest request) { this.request = request; } public String toJson(){ if(request==null) return JsonUtils.obj2json(this); else return toJson(request); } public String toJson(HttpServletRequest request){ return JsonUtils.obj2json(this); } }
注：该类中引用了JSON数据转换工具类，可以改成自己需要的，也可以删除。
