类转换
package zxc.utils;import java.lang.reflect.Member;import java.util.Collection;import java.util.HashMap;import java.util.Map;import java.util.SortedMap;import java.util.TreeMap;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ConcurrentMap;import org.springframework.util.StringUtils;import com.opensymphony.xwork2.inject.Inject;import com.opensymphony.xwork2.util.ObjectTypeDeterminer;import com.opensymphony.xwork2.util.XWorkBasicConverter;import com.opensymphony.xwork2.util.XWorkConverter;public class CustomShareConverter extends XWorkBasicConverter {public static final StringSEQUENCE_SEPARATOR= ",";public static final StringMAP_SEPARATOR= ":";private ObjectTypeDeterminerobjectTypeDeterminer;@Injectpublic void setObjectTypeDeterminer(ObjectTypeDeterminer det) {this.objectTypeDeterminer = det;}/** * 这里的toType一定是一个在配置文件将此转换器作为它的转换器的类或者是String类 */@SuppressWarnings("unchecked")@Overridepublic Object convertValue(Map context, Object target, Member member, String property, Object value, Class toType) {if (value == null || toType == String.class || ((String[]) value).length != 1) {//注意第一个条比较怪,具体解释是:1.如果为null交给超类;2.如果向前台转,也交给超类;//3.前台向后台转,且value不为null,但是前台传递同一个name多于一个值,则仍然使用超类转换return super.convertValue(context, target, member, property, value, toType);} String strValue = ((String[]) value)[0];//我现存在认为只要前台传值至少会有一个元素,放在这个表达式在这里确认一下if (toType == Boolean.class) {if (value == null || !StringUtils.hasText(strValue) || "null".equals(strValue)) {return null;} else if ("true".equals(strValue) || "1".equals(strValue)) {return Boolean.TRUE;} else {//注意:除去true,1,与null全部返回falsereturn Boolean.FALSE;}} else if (toType.isArray() || Collection.class.isAssignableFrom(toType)) {//向台向后台转,并且是单参数(即序列转数组)String sequence = strValue;if (!StringUtils.hasText(sequence)||"null".equals(sequence)) {return null;//对序列情况的处理}//这里重写了拆分逻辑value = new SequenceSplitor(sequence).split(SEQUENCE_SEPARATOR.charAt(0));return super.convertValue(context, target, member, property, value, toType);} else if (Map.class.isAssignableFrom(toType)) {//超类并没有给出对map情况的处理,这里直接将它处理掉,但是map中的成员仍然是依赖超类处理return convertToMap(context, target, member, property, value, toType);}throw new RuntimeException("预期外的类型");}//将一个序列转换成一个Mapprivate Object convertToMap(Map<?, ?> context, Object target, Member member, String property, Object value, Class<?> toType) {String sequence = ((String[]) value)[0];String[] splitArray = new SequenceSplitor(sequence).split(SEQUENCE_SEPARATOR.charAt(0));Class<?> keyClass = String.class;Class<?> valueClass = String.class;if (target != null) {keyClass = this.objectTypeDeterminer.getKeyClass(target.getClass(), property);valueClass = this.objectTypeDeterminer.getElementClass(target.getClass(), property, null);}Map<Object, Object> map = createMap(context, target, member, property, value, toType, splitArray.length);for (int index = 0; index < splitArray.length; index++) {String keyValue = splitArray[index];//这里重写了拆分逻辑String[] keyValuePair = new SequenceSplitor(keyValue).split(MAP_SEPARATOR.charAt(0));//注意这个地方注入xworkConverter来进行转换,主要是怕遗漏Map中的键值有可能需要定制转换器,还有一点需要注意,传值使用字符串数组以模拟前台Object key = XWorkConverter.getInstance().convertValue(context, null, null, null, new String[] { keyValuePair[0] }, keyClass);Object val = XWorkConverter.getInstance().convertValue(context, null, null, null, new String[] { keyValuePair[1] }, valueClass);map.put(key, val);}return map;}private Map<Object, Object> createMap(Map<?, ?> context, Object target, Member member, String property, Object value, Class<?> toType, int size) {Map<Object, Object> map;if (toType == ConcurrentMap.class) {if (size > 0) {map = new ConcurrentHashMap<Object, Object>(size);} else {map = new ConcurrentHashMap<Object, Object>();}} else if (toType == SortedMap.class) {map = new TreeMap<Object, Object>();} else {if (size > 0) {map = new HashMap<Object, Object>(size);} else {map = new HashMap<Object, Object>();}}return map;}}?