JavaBean 成员命名规范

在eclipse中自动生成setters()和getters()User.javaprivate boolean active ;//getter()public boolean isActive() {return isActive;}//setter()public void setActive(boolean active ) { this.active = active; } //jsp   页面中${user.isActive}==error==javax.servlet.jsp.el.ELException: Unable to find a value for “isActive” in object of class “com.mycompany.domain.User” using operator “.”==cuz==JavaBean命名规范里面规定，对于primitive和自定义类类型的属性property（小写），getter和setter方法就是getProperty和setProperty（第一个字母变大写，前面再加get或set）。而对于类型为boolean的属性，getter方法还可以写为isProperty（getProperty仍然可用），而且，如果属性的前两个字母是is（两个小写），则getter与property完全同名（比如上面属性isActive的getter就是isActive()）。① JSP里只能用${user.active}来访问（注意大小写）。② 把active的getter()手动写为getActive(),JSP还是和其他非boolean型属性一样使用。-------------------------------------------------------------------------------------------------------------------------------------------------1. UserAdress 这样的字段() 为避免出错 声明的时候 private String userAdress;  这样生成的setter&getter就比较规范，符合javaBean的规范方便使用。public void setUserAdress(String userAdress) { this.userAdress = userAdress; } public String getUserAdress() { return userAdress; } 2. PDFSize 这样的字段可以不用做任何修改。(下面引用中会讲到URL)3. cInfo(一般性地说，第一个字母小写，第二个字母大写属性命名在开发需求中经常有遇到，比如c是代表用户数据，i代表输入的数据) 这样的字段需要把I变回i，总而言之： 命名属性时，第二个字符最好是小写字母。这个方法不需要做更多地修改，符合所有规范，最为稳妥。否则自动生成的setter&getter都是setCInfo(),getCInfo();运行出错：Caused by: org.hibernate.PropertyNotFoundException: Could not find a getter for cInfo in class Userat org.hibernate.property.BasicPropertyAccessor.createGetter(BasicPropertyAccessor.java:282)at org.hibernate.property.BasicPropertyAccessor.getGetter(BasicPropertyAccessor.java:275)---------------------------------------------------------------------------------------------------------------------------------------------------引用 http://www.360doc.com/content/08/1231/15/94066_2235043.shtml 跟踪到org.hibernate.property.BasicPropertyAccessor类中的getterMethod(Class theClass, String propertyName)方法：1    private static Method getterMethod(Class theClass, String propertyName) {Method[] methods = theClass.getDeclaredMethods();for (int i = 0; i < methods.length; i++) {// only carry on if the method has no parametersif (methods[i].getParameterTypes().length == 0) {String methodName = methods[i].getName();// try "get"if (methodName.startsWith("get")) {String testStdMethod = Introspector.decapitalize(methodName.substring(3));String testOldMethod = methodName.substring(3);if (testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName)) {return methods[i];}}// if not "get" then try "is"if (methodName.startsWith("is")) {String testStdMethod = Introspector.decapitalize(methodName.substring(2));String testOldMethod = methodName.substring(2);if (testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName)) {return methods[i];}}}}return null;}getterMethod()对Company类中声明的方法进行遍历，找到与属性名匹配的方法，即属性的getter方法。比较分两部分，第一部分，针对primitive和自定义类类型的属性；第二部分，针对boolean类型的属性（由于boolean类型属性的getter方法的特殊性）。跟踪发现，methodName的值为“getSAddress”，propertyName的值为“sAddress”，testOldMethod的值为“SAddress”，testStdMethod的值为“SAddress”。testStdMethod和testOldMethod相同，而它们都不匹配propertyName！因此，getterMethod()中找不到与属性sAddress匹配的getter方法，getterMethod()返回null，导致异常。问题出在Introspector.decapitalize()方法。decapitalize()源码如下：1    /*** Utility method to take a string and convert it to normal Java variable* name capitalization. This normally means converting the first* character from upper case to lower case, but in the (unusual) special* case when there is more than one character and both the first and* second characters are upper case, we leave it alone.** Thus "FooBah" becomes "fooBah" and "X" becomes "x", but "URL" stays* as "URL".** @param name The string to be decapitalized.* @return The decapitalized version of the string.*/public static String decapitalize(String name) {if (name == null || name.length() == 0) {return name;}if (name.length() > 1 && Character.isUpperCase(name.charAt(1)) &&Character.isUpperCase(name.charAt(0))){return name;}char chars[] = name.toCharArray();chars[0] = Character.toLowerCase(chars[0]);return new String(chars);}