commons-dbutils的研究和开发应用（三）
/**
* 将一个ResultSet转换为一个List对象
*/
public List toBeanList(ResultSet rs, Class type) throws SQLException {
List results = new ArrayList();
if (!rs.next()) {
return results;
}
PropertyDescriptor[] props = this.propertyDescriptors(type);
ResultSetMetaData rsmd = rs.getMetaData();
int[] columnToProperty = this.mapColumnsToProperties(rsmd, props);
do {
results.add(this.createBean(rs, type, props, columnToProperty));
} while (rs.next());
return results;
}
private Object createBean(ResultSet rs, Class type,
PropertyDescriptor[] props, int[] columnToProperty)
throws SQLException {
Object bean = this.newInstance(type);
for (int i = 1; i < columnToProperty.length; i++) {
if (columnToProperty[i] == PROPERTY_NOT_FOUND) {
continue;
}
PropertyDescriptor prop = props[columnToProperty[i]];
Class propType = prop.getPropertyType();
Object value = this.processColumn(rs, i, propType);
if (propType != null && value == null && propType.isPrimitive()) {
value = primitiveDefaults.get(propType);
}
this.callSetter(bean, prop, value);
}
return bean;
}
/**
*设置对象的setter方法的应用
*/
private void callSetter(Object target, PropertyDescriptor prop, Object value)
throws SQLException {
Method setter = prop.getWriteMethod();
if (setter == null) {
return;
}
Class[] params = setter.getParameterTypes();
try {
// convert types for some popular ones
if (value != null) {
if (value instanceof java.util.Date) {
if (params[0].getName().equals("java.sql.Date")) {
value = new java.sql.Date(((java.util.Date) value).getTime());
} else
if (params[0].getName().equals("java.sql.Time")) {
value = new java.sql.Time(((java.util.Date) value).getTime());
} else
if (params[0].getName().equals("java.sql.Timestamp")) {
value = new java.sql.Timestamp(((java.util.Date) value).getTime());
}
}
}
// Don't call setter if the value object isn't the right type
if (this.isCompatibleType(value, params[0])) {
setter.invoke(target, new Object[] { value });
} else {
throw new SQLException(
"Cannot set " + prop.getName() + ": incompatible types.");
}
} catch (IllegalArgumentException e) {
throw new SQLException(
"Cannot set " + prop.getName() + ": " + e.getMessage());
} catch (IllegalAccessException e) {
throw new SQLException(
"Cannot set " + prop.getName() + ": " + e.getMessage());
} catch (InvocationTargetException e) {
throw new SQLException(
"Cannot set " + prop.getName() + ": " + e.getMessage());
}
}