快捷導(dǎo)航

Java中Boolean與字符串或者數(shù)字1和0的轉(zhuǎn)換實(shí)例

更新時(shí)間：2017年07月11日 09:09:04 投稿：jingxian

下面小編就為大家?guī)硪黄狫ava中Boolean與字符串或者數(shù)字1和0的轉(zhuǎn)換實(shí)例。小編覺得挺不錯(cuò)的，現(xiàn)在就分享給大家，也給大家做個(gè)參考。一起跟隨小編過來看看吧

mysql有個(gè)字段是bit，只存儲1和0，是二進(jìn)制存儲，那么在java的dao層如何映射成boolean呢

@Column(name="is_standard")
private boolean isStandard;

public void setIsStandard(boolean isStandard){
 this.isStandard = isStandard;
}

public boolean getIsStandard(){
 return isStandard;
}

其實(shí)就是在底層dao做反射的時(shí)候，先判斷字段(比如isStandard)的字段類型是否為boolean，如果是，則在查出數(shù)據(jù)庫字段bit is_standard的時(shí)候，做轉(zhuǎn)換

private List<T> populateData(ResultSet resultSet, Class<T> clazz) throws Exception {
 List<T> dataList = new ArrayList<T>();
 List<Field> fieldList = MappingAnnotationUtil.getAllFields(clazz);

 ResultSetMetaData rsmd = resultSet.getMetaData();
 int columnsCount = rsmd.getColumnCount();
 List<String> columnNameList = new ArrayList<String>();
 for(int i = 0; i < columnsCount; i++){
  columnNameList.add(rsmd.getColumnLabel(i+1).toLowerCase());
 }

 while (resultSet.next()) { 
  T bean = clazz.newInstance();
  for(Field f : fieldList) {
  String columnName = MappingAnnotationUtil.getDBCloumnName(clazz, f).toLowerCase();
  if(columnNameList.contains(columnName)) {
   Object columnValueObj = null;
   Class<?> filedCls = f.getType();
   
   if(filedCls == int.class || filedCls == Integer.class) {
   columnValueObj = resultSet.getInt(columnName);
   } else if(filedCls == String.class) {
   columnValueObj = resultSet.getString(columnName);
   } else if(filedCls == boolean.class || filedCls == Boolean.class) {
   columnValueObj = resultSet.getBoolean(columnName);
   } else if(filedCls == byte.class || filedCls == Byte.class) {
   columnValueObj = resultSet.getByte(columnName);
   } else if(filedCls == short.class || filedCls == Short.class) {
   columnValueObj = resultSet.getShort(columnName);
   } else if(filedCls == long.class || filedCls == Long.class) {
   columnValueObj = resultSet.getLong(columnName);
   } else if(filedCls == float.class || filedCls == Float.class) {
   columnValueObj = resultSet.getFloat(columnName);
   } else if(filedCls == double.class || filedCls == Double.class) {
   columnValueObj = resultSet.getDouble(columnName);
   } else if(filedCls == BigDecimal.class) {
   columnValueObj = resultSet.getBigDecimal(columnName);
   } 
   
   else {
   columnValueObj = resultSet.getObject(columnName);
   }
   
   if (columnValueObj != null) {
   Method setterMethod = MappingAnnotationUtil.getSetterMethod(clazz, f);
   setterMethod.invoke(bean, new Object[] { columnValueObj });
   }
  }
  }
  dataList.add(bean);
 }
 return dataList;
 }

注意這個(gè)

else if(filedCls == boolean.class || filedCls == Boolean.class) {
 columnValueObj = resultSet.getBoolean(columnName);
}

resultSet.getBoolean(columnName) 就是轉(zhuǎn)換的方法，具體實(shí)現(xiàn)為

 for (int i = 0; i < trueStrings.length; ++i) {
  if (trueStrings[i].equals(stringValue)) {
   return type.cast(Boolean.TRUE);
  }
  }

  for (int i = 0; i < falseStrings.length; ++i) {
  if (falseStrings[i].equals(stringValue)) {
   return type.cast(Boolean.FALSE);
  }
  }