快速的构建Map<K,V>实例 Easy to build a Map<K,V> instance.
MapBuilder<String, String> builder =
MapBuilder.begin("hello", "world");
use method begin to create a MapBuilder instance, and indicate the generic type of the Map<K,V>, the arguments of method begin will be the first Entry in the Map
builder.and("good", "bye")
.and("fine", "thank u")
.and("ni", "hao");
Map<String, String> map = builder.build();
type of MapBuilder<K,V> is decided by the arguments' type of method begin
MapBuilder<String, Integer> builder =
MapBuilder.begin("hello", 100);
MapBuilder<String, Object> builder =
MapBuilder.begin("a-key", (Object) "haha"));
somewhere u need a map
MapBuilder.begin("example", (Object) "1")
.and("num", 100)
.and("disabled", false)
.and("params", MapBuilder.begin("param1", (Object) "nothing")
.and("param2", new int[]{0, 1, 2})
.and("bool", true)
.and("counter", new Integer(5))
.build())
.and("ending", true)
.build();
u can get a Map like:
{
"example": "1",
"num": 100,
"disabled": false,
"params": {
"param1": "nothing",
"param2": [0, 1, 2],
"bool": true,
"counter": 5
},
"ending": true
}
try it!
see tests
- construct
use static method com.cloume.commons.beanutils.Updater.wrap(R) create new instance, Updater.wrap(theObjectYouWantToUpdate) return the Updater instance
class UpdatableClass { ... }
Updater<UpdatableClass> updater = Updater.wrap(new UpdatableClass());
- keys mapping
method com.cloume.commons.beanutils.Updater.mapping(String, String) use to map a key name to another, for example a class has a field named someField, when there is a key named anotherField, can use the mapping set the value of anotherField to the someField of target class instance. and method mapping return the Updater instance self, so can write multi-mapping in chain
Updater<UpdatableClass> updater = updater
.mapping("anotherField", "someField")
.mapping("helloField", "hiField");
- update
there are two overwrited methods com.cloume.commons.beanutils.Updater.update(Map<String, Object>) and com.cloume.commons.beanutils.Updater.update(Map<String, Object>, IConverter), use to update the target instance from a Map<String, Object>.
- update without converter
example:
class UpdatableClass {
String someField;
int hiField;
}
Map<String, Object> from = new HashMap<String, Object>();
from.put("someField", "hello,world");
from.put("helloField", 100); ///see mapping
UpdatableClass updated = updater.update(from);
- update with converter
converter com.cloume.commons.beanutils.IConverter have two methods com.cloume.commons.beanutils.IConverter.convert(String, Object) must be implemented, and com.cloume.commons.beanutils.IConverter.pair(String, Object) provide an easy way create new Entry<K,V> instance.
when using converter you can both maping key and modify the value to fit the class field needs.
example:
ObjectToUpdate updated = Updater.wrap(new ObjectToUpdate()).mapping("longValue2", "longValue").update(from,
/// java8 can use lambda
new IConverter() {
@SuppressWarnings("unchecked")
@Override
public Entry<String, Object> convert(String key, Object value) {
switch (key) {
case "intValue": {
return pair(key, Integer.parseInt(String.valueOf(value)));
}
case "arrayValue": {
return pair(key, StringUtils.split(String.valueOf(value), ','));
}
case "stringValue2": {
return pair("stringValue", value);
}
case "classValue": {
return pair(key, Updater.wrap(new InnerClass()).update((Map<String, Object>) value));
}
}
return pair(key, value); ///pass through
}
});
- complex field
example:
class InnerClass { String innerField; }
class UpdatableClass {
String someField;
int hiField;
InnerClass classField;
}
Map<String, Object> from = new HashMap<String, Object>();
from.put("classField.innerField", "hello,world");
UpdatableClass updated = updater.update(from);
RESTful api如果采用JSON承载数据的话, 经常性的POST这样的数据:
{
"foo": "hello,world",
"foo3": 100,
"foo8": { "question": "who am i?" }
}
为了安全，后端也需要对提交的数据进行有效性验证。
IResultCallback callback = ...;
Map<String, Object> target = ...;
boolean result = new Verifier()
.result(callback) //这是可选的
//rule方法有5个重载
.rule("foo") //必须存在foo属性
.rule("foo2", "[0-9]{1,3}") //foo2属性必须存在, 并且值必须是1到3位的数字字符串
.rule("foo3", true, "[0-9]{1,3}") //foo3属性可以不存在, 如果有的话, 其值必须是1到3位的数字字符串
.rule("foo4", new IChecker() {
public boolean check(Object value) { ... }
}) //通过实现IChecker对foo4值进行检查
.rule("foo5", true, new IChecker() {
public boolean check(Object value) { ... }
}) //通过实现IChecker对foo5值进行检查, foo5可以不存在
.verify(target);
上述例子是一般用法, 如果设置了IResultCallback的话, 除了返回结果result以外, IResultCallback的方法void result(boolean success, String reason);中, 也可以获得校验结果和原因(第二个参数reason). 如果是java8+可以用lambda很方便的进行调用
目前已经实现的检查器有3个:
- AlwaysTrueChecker
- AlwaysFalseChecker
- RegexChecker 通过正则表达式进行检查
如果这些检查器不够用, 可以像例子中的foo4/foo5一样自己实现新的检查器