支持联合主键的基类设计
1. 子类的主键名称不相同。
2. 基类可能支持联合主键，也可能是单一主键。
实现方法：
添加一个参数列表，来记录主键的名称，如下：
private String[] primaryKey; public void sPrimaryKey(String... primaryKey){ Assert.notEmpty(primaryKey, "'primaryKey' must not be empty"); this.primaryKey = primaryKey; } public String[] gPrimaryKey() { return primaryKey; }
其中不用setter和getter，是为了避免子类与xml转换时把primaryKey也当做属性参数。这里primaryKey只是辅助基类。
我们可以通过primaryKey的值，来获取子类主键的值。如下：
public Object[] gID() throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException { int i = 0; if(this.primaryKey != null) i = this.primaryKey.length; Object[] id = new Object[i]; while(i > 0){ Field f = null; try{ f = this.getClass().getDeclaredField(primaryKey[i-1]); }catch (NoSuchFieldException e){ if(this.getClass().getSuperclass() != null) f = this.getClass().getSuperclass().getDeclaredField(primaryKey[i-1]); } f.setAccessible(true); id[i-1] = f.get(this); i--; } return id; } public boolean sID(Object[] para) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException { int i = 0; if(this.primaryKey != null) i = this.primaryKey.length; int j = 0; while(j < i){ Field f = null; try{ f = this.getClass().getDeclaredField(primaryKey[i-1]); }catch (NoSuchFieldException e){ if(this.getClass().getSuperclass() != null) f = this.getClass().getSuperclass().getDeclaredField(primaryKey[i-1]); } f.setAccessible(true); f.set(this, para[j]); j++; } boolean ret =false; return ret; }
其中使用getDeclaredField来获取主键的属性，然后进行set或者get。
注意如果主键是继承自父类的，则需要从父类获取。如上的catch块。
具体使用，如下：
public boolean delete(T entity){ Object[] id = null; try { id = entity.gID(); } catch (IllegalArgumentException | IllegalAccessException | NoSuchFieldException | SecurityException e) { // TODO Auto-generated catch block e.printStackTrace(); } int i = id.length; String url = this.URL + id[i-1]; i--; while(i > 0){ i--; url +=("/"+id[i]); } Document dom = sendDelete(url); return judgeStatus(dom); } public boolean update(T entity){ Object[] id = null; try { id = entity.gID(); } catch (IllegalArgumentException | IllegalAccessException | NoSuchFieldException | SecurityException e) { // TODO Auto-generated catch block e.printStackTrace(); } int i = id.length; String url = this.URL + id[i-1]; i--; while(i > 0){ i--; url +=("/"+id[i]); } Document dom = sendPut(url, entity.Object2Map()); return judgeStatus(dom); }
将继承的子类属性转换成map<paraName, paraValue>的操作如下：
public Map<String, String> Object2Map() { Map<String, String> params = new HashMap<String, String>(); Object obj = null; String value; try { Class<?> theclass = this.getClass(); Class<?> superclass = theclass.getSuperclass(); Field[] fields = theclass.getDeclaredFields(); Field[] superfields = null; if(superclass != null){ superfields = superclass.getDeclaredFields(); } Field[] allFields = Arrays.copyOf(fields,fields.length+superfields.length); System.arraycopy(superfields, 0, allFields, fields.length, superfields.length); for (Field field:allFields) { field.setAccessible(true); if (field.isAccessible()) { obj = field.get(this); if (obj != null) { if(field.getType().getName().equals("java.util.Date")) { value = MyDateFormat.DateToString(Date.class.cast(obj)); } else { value = field.getType().cast(obj) .toString(); } params.put(field.getName(), value); } } } } catch (IllegalAccessException | IllegalArgumentException | SecurityException e) { Logger.loging(Level.SEVERE, "%s Exception, message: %s.\n", e.getClass() .getName(), e.getMessage()); return null; } return params; }
从map转变为object
public boolean loadFromParams(Map<String, String> params) { try { Class<?> theclass = this.getClass(); Class<?> superclass = theclass.getSuperclass(); Field[] fields = theclass.getDeclaredFields(); Field[] superfields = null; if(superclass != null){ superfields = superclass.getDeclaredFields(); } Field[] allFields = Arrays.copyOf(fields,fields.length+superfields.length); System.arraycopy(superfields, 0, allFields, fields.length, superfields.length); for (Field field:allFields) { field.setAccessible(true); if (field.isAccessible()) { String s = params.get(field.getName()); if (s != null) { if(field.getType().getName().equals("java.util.Date")) { Date obj = MyDateFormat.StringToDate(s); field.set(this, obj); } else { Object obj = field.getType() .getConstructor(new Class[] { String.class }) .newInstance(s); field.set(this, obj); } } } } } catch (IllegalAccessException | SecurityException | IllegalArgumentException | InstantiationException | NoSuchMethodException | InvocationTargetException e) { Logger.loging(Level.SEVERE, "%s Exception, message: %s.\n", e.getClass() .getName(), e.getMessage()); return false; } return true; }