看朋友写数据库查询，获取结果的时候，每次都会写一大堆代码，我想起以前Java里写过一个公用的方法。
因为初学Android所以就试着写一个，可以满足我的需求。
有什么需要改的或者优化的还请赐教。
代码如下：
package cn.com.choicesoft.weiqian.util;import java.lang.reflect.Method;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;/** [email protected]:M.c [email protected]:数据库公用查询结果 处理类 [email protected]:2014-1-20 [email protected]:[email protected] */public class ListProcessor { private DBManager db; public DBManager getDb(Context context) { if(db==null){ db = new DBManager(context); } return db; } /** * 根据传入实体返回对应的实体数组 * @param sql SQL语句 * @param selectionArgs SQL条件 * @param context Activity * @param cal 实体类 【实体内属性只支持：String,Integer,Float,Double,Boolean,Short,Long,Character(char)】 * @return List<T> */ public <T> List<T> query(String sql,String[] selectionArgs,Context context,Class<T> cal){ SQLiteDatabase database = getDb(context).openDatabase(); Cursor c = database.rawQuery(sql, selectionArgs); Method[] methods = cal.getMethods(); List<T> list=new ArrayList<T>(); while (c.moveToNext()) { Object obj=null; try { obj=cal.newInstance(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } for (Method method : methods) { String methodName=method.getName(); if(methodName.matches("^set[A-Z]\\w+$")){ String name=methodName.substring(3, methodName.length()).toUpperCase(); for (int i=0;i<c.getColumnCount();i++) { if(name.equalsIgnoreCase(c.getColumnName(i))){ try { typeDivision(method,c.getString(i),cal,obj); break; } catch (Exception e) { e.printStackTrace(); } } } } } list.add((T)obj); } if(c!=null){ c.close(); } if(database!=null){ database.close(); } return list; } /** * 不同类型转换 * @param method * @param value * @param cla * @throws Exception */ public void typeDivision(Method method, Object value, Class<?> cls,Object obj) throws Exception { Object typeName = method.getParameterTypes()[0]; Method setMethod = null; if (typeName == String.class) { setMethod = cls.getMethod(method.getName(), String.class); setMethod.invoke(obj, value.toString()); }else if (typeName == Double.class||typeName.toString().equals("double")){ setMethod = cls.getMethod(method.getName(), typeName == Double.class?Double.class:double.class); setMethod.invoke(obj, new Double(value.toString())); }else if (typeName == Integer.class||typeName.toString().equals("int")) { setMethod = cls.getMethod(method.getName(), typeName == Integer.class?Integer.class:int.class); setMethod.invoke(obj, Integer.valueOf(value.toString())); }else if (typeName == Long.class||typeName.toString().equals("long")) { setMethod = cls.getMethod(method.getName(), typeName == Long.class?Long.class:long.class); setMethod.invoke(obj, Long.valueOf(value.toString())); } else if (typeName == Character.class||typeName.toString().equals("char")) { setMethod = cls.getMethod(method.getName(),typeName == Character.class?Character.class:char.class); setMethod.invoke(obj, value.toString().charAt(0)); } else if (typeName == Boolean.class||typeName.toString().equals("boolean")) { setMethod = cls.getMethod(method.getName(), typeName == Boolean.class?Boolean.class:boolean.class); setMethod.invoke(obj, new Boolean(value.toString())); } else if (typeName == Float.class||typeName.toString().equals("float")) { setMethod = cls.getMethod(method.getName(), typeName == Float.class?Float.class:float.class); setMethod.invoke(obj, Float.valueOf(value.toString())); } else if (typeName == Short.class||typeName.toString().equals("short")) { setMethod = cls.getMethod(method.getName(), typeName == Short.class?Short.class:short.class); setMethod.invoke(obj, Short.valueOf(value.toString())); } }}
声明
欢迎转载，但请保留文章原始出处
[Iteye]-http://jnwsczh.iteye.com/blog/2019454