JFinal ： Validator分析

                         1.源码讨论

@Before(BlogValidator.class)	public void save() {		getModel(Blog.class).save();		redirect("/blog");	}

2.@Before(BlogValidator.class)
这段代码是在方法执行前会调用BlogValidator拦截器

public class BlogValidator extends Validator {		protected void validate(Controller controller) {		validateRequiredString("blog.title", "titleMsg", "请输入Blog标题!");		validateRequiredString("blog.content", "contentMsg", "请输入Blog内容!");	}		protected void handleError(Controller controller) {		controller.keepModel(Blog.class);				String actionKey = getActionKey();		if (actionKey.equals("/blog/save"))			controller.render("add.html");		else if (actionKey.equals("/blog/update"))			controller.render("edit.html");	}}

3.会调用Validator中的intercept方法

Validator validator = null;		try {validator = getClass().newInstance();}		catch (Exception e) {throw new RuntimeException(e);}				validator.controller = invocation.getController();		validator.invocation = invocation;				try {validator.validate(validator.controller);} 		catch (ValidateException e) {/* should not be throw */}			// short circuit validate need this				if (validator.invalid)			validator.handleError(validator.controller);		else			invocation.invoke();

4. validator.validate(validator.controller)这段代码是关键

validateRequiredString("blog.title", "titleMsg", "请输入Blog标题!");validateRequiredString("blog.content", "contentMsg", "请输入Blog内容!");

5.validateRequiredString,这个代码非常简单就是request获取参数值,如果为空,放到request中去

/**	 * Validate required string.	 */	protected void validateRequiredString(String field, String errorKey, String errorMessage) {		String value = controller.getPara(field);		if (value == null || "".equals(value.trim()))			addError(errorKey, errorMessage);	}

6.当我们这个字段保存填为空的时候,我们就会执行如下代码啦

protected void handleError(Controller controller) {		controller.keepModel(Blog.class);				String actionKey = getActionKey();		if (actionKey.equals("/blog/save"))			controller.render("add.html");		else if (actionKey.equals("/blog/update"))			controller.render("edit.html");	}

7.controller.keepModel(Blog.class); 

public Controller keepModel(Class modelClass) {		String modelName = StringKit.firstCharToLowerCase(modelClass.getSimpleName());		keepModel(modelClass, modelName);		return this;	}

8.StringKit.firstCharToLowerCase(modelClass.getSimpleName())  其实就是首字母小写
9.keepModel(modelClass, modelName);这行代码很简单啦

public Controller keepModel(Class modelClass, String modelName) {		Object model = ModelInjector.inject(modelClass, modelName, request, true);		request.setAttribute(modelName, model);		return this;	}

10.Object model = ModelInjector.inject(modelClass, modelName, request, true); 这段代码就是运用反射给变量注入值

@SuppressWarnings({ "rawtypes", "unchecked" })	public static final <T> T inject(Class<?> modelClass, String modelName, HttpServletRequest request, boolean skipConvertError) {		Object model = null;		try {			model = modelClass.newInstance();		} catch (Exception e) {			throw new ModelInjectException(e);		}				if (model instanceof Model)			injectActiveRecordModel((Model)model, modelName, request, skipConvertError);		else			injectCommonModel(model, modelName, request, modelClass, skipConvertError);				return (T)model;	}

11.上面的代码会执行下面这个方法的代码,下面代码的核心意义就根据数据库表的字段和类型将值放入到Model的Map中

@SuppressWarnings("rawtypes")	private static final void injectActiveRecordModel(Model<?> model, String modelName, HttpServletRequest request, boolean skipConvertError) {		TableInfo tableInfo = TableInfoMapping.me().getTableInfo(model.getClass());				String modelNameAndDot = modelName + ".";				Map<String, String[]> parasMap = request.getParameterMap();		for (Entry<String, String[]> e : parasMap.entrySet()) {			String paraKey = e.getKey();			if (paraKey.startsWith(modelNameAndDot)) {				String paraName = paraKey.substring(modelNameAndDot.length());				Class colType = tableInfo.getColType(paraName);				if (colType == null)					throw new ActiveRecordException("The model attribute " + paraKey + " is not exists.");				String[] paraValue = e.getValue();				try {					// Object value = Converter.convert(colType, paraValue != null ? paraValue[0] : null);					Object value = paraValue[0] != null ? TypeConverter.convert(colType, paraValue[0]) : null;					model.set(paraName, value);				} catch (Exception ex) {					if (skipConvertError == false)						throw new ModelInjectException("Can not convert parameter: " + modelNameAndDot + paraName, ex);				}			}		}	}