通过反射把map中的属性赋值到实体类bean对象中
使用过struts2后感觉最方便的就是这个框架能自动把表单的参数赋值到action里面的对象中
但现在主要使用Spring框架的MVC，虽然也有@ModelAttribute可以使用但是明显感觉不方便。
好吧，那就自己再造一个轮子吧。
原理都知道，就是利用反射进行字段的赋值，下面贴代码
主要类如下：
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class MapToEntryConvertUtils {
private static Log log = LogFactory.getLog(MapToEntryConvertUtils.class);
/**
* 缓存类的属性信息
*/
private static Map<String,ConvertEntryItem> convertItemCache = new HashMap<String,ConvertEntryItem>();
/**
* Map转换为Entry
* @param <T>
* @param valueMap 泛型类型为<String,Object>
* @param entityClass
* @param prefix 从map中取值的key为 prefix + attr
* @return
*/
@SuppressWarnings("rawtypes")
public static <T> T convert(Map valueMap,Class<T> entityClass,String prefix){
ConvertEntryItem convertItem = convertItemCache.get(entityClass.getName());
if(convertItem == null){
convertItem = ConvertEntryItem.createConvertItem(entityClass);
convertItemCache.put(entityClass.getName(), convertItem);
}
//entityClass 的可访问字段名
List<String> fieldNameList = convertItem.getFieldNameList();
//字段名和对应的set方法映射
Map<String,Method> fieldSetMethodMap = convertItem.getFieldSetMethodMap();
T entity = null;
try {
entity = entityClass.newInstance();
} catch (InstantiationException e) {
log.error("create "+entityClass.getName()+" instance failed, Do it has a empty constructed function ?", e);
return null;
} catch (IllegalAccessException e) {
log.error("create "+entityClass.getName()+" instance failed, Do it has a empty constructed function ?", e);
return null;
}
Object fieldValue = null;
Method m;
Class<?>[] parameterTypes;
Object targetValue;
if(prefix == null) prefix = "";
//遍历字段列表，分别调用每个字段的set方法
for(String fieldName: fieldNameList){
fieldValue = valueMap.get(prefix+fieldName);
if(fieldValue == null) continue;
m = fieldSetMethodMap.get(fieldName);
if(m == null) continue;
//set方法的参数类型
parameterTypes = m.getParameterTypes();
if(parameterTypes.length != 1) continue; //只支持单个参数的set方法
//如果第一个参数类型和当前类型相同，则直接使用
if(parameterTypes[0].isAssignableFrom(fieldValue.getClass())){
targetValue = fieldValue;
}else{
//转换当前的值为目标参数类型
targetValue = ConvertFactory.convert(parameterTypes[0], fieldValue);
}
if(targetValue != null){
try {
//调用set方法进行赋值
m.invoke(entity, targetValue);
} catch (Exception e) {
log.error("set value failed:{method="+m.getName()+",value="+targetValue+"}", e);
}
}
}
return entity;
}
static class ConvertEntryItem{
private List<String> fieldNameList = new ArrayList<String>();
private Map<String,Method> fieldSetMethodMap = new HashMap<String, Method>();
private ConvertEntryItem(){}
public List<String> getFieldNameList() {
return fieldNameList;
}
public Map<String, Method> getFieldSetMethodMap() {
return fieldSetMethodMap;
}
private void parseEntry(Class<?> cls){
Field[] allField = cls.getDeclaredFields();
Method m = null;
String methodName;
for(Field f: allField){
methodName = f.getName();
methodName = "set"+methodName.substring(0, 1).toUpperCase()+methodName.substring(1);
try {
//只返回和当前字段类型相符的set方法，不支持多参数以及不同类型的set方法
m = cls.getDeclaredMethod(methodName, f.getType());
if(m != null){
fieldNameList.add(f.getName());
fieldSetMethodMap.put(f.getName(), m);
}
} catch (SecurityException e) {
log.error("parseEntry failed: SecurityException", e);
} catch (NoSuchMethodException e) {
log.info("NoSuchMethod in "+cls.getName()+": "+methodName);
}
}
}
public static ConvertEntryItem createConvertItem(Class<?> cls){
ConvertEntryItem ci = new ConvertEntryItem();
ci.parseEntry(cls);
return ci;
}
}
}
转换接口贴上，实话实说，偷的Spring里面的接口
/**
* 类型转换接口
* @param <S> 源类型
* @param <T> 目标类型
*/
public interface Convert<S,T> {
T convert(S source);
}
再来个具体调用转换的类：
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class ConvertFactory {
private static Log log = LogFactory.getLog(ConvertFactory.class);
public static Map<String,Convert<?,?>> convertHandlers = new HashMap<String, Convert<?,?>>();
/**
* 注册转换器
*/
static{
convertHandlers.put(String[].class.getName()+"To"+Float[].class.getName(), new ObjectArrToFloatArrConvert());
convertHandlers.put(String[].class.getName()+"To"+float[].class.getName(), new ObjectArrToFloaArrConvert());
convertHandlers.put(String[].class.getName()+"To"+Double[].class.getName(), new ObjectArrToDoubleArrConvert());
convertHandlers.put(String[].class.getName()+"To"+double[].class.getName(), new ObjectArrToDoublArrConvert());
convertHandlers.put(String[].class.getName()+"To"+Integer[].class.getName(), new ObjectArrToIntegerArrConvert());
convertHandlers.put(String[].class.getName()+"To"+int[].class.getName(), new ObjectArrToIntArrConvert());
convertHandlers.put(String.class.getName()+"To"+Date.class.getName(), new ObjectToDateConvert());
convertHandlers.put(String.class.getName()+"To"+Double.class.getName(), new ObjectToFloatConvert());
convertHandlers.put(String.class.getName()+"To"+double.class.getName(), new ObjectToFloatConvert());
convertHandlers.put(String.class.getName()+"To"+Float.class.getName(), new ObjectToFloatConvert());
convertHandlers.put(String.class.getName()+"To"+float.class.getName(), new ObjectToFloatConvert());
convertHandlers.put(String.class.getName()+"To"+Integer.class.getName(), new ObjectToIntegerConvert());
convertHandlers.put(String.class.getName()+"To"+int.class.getName(), new ObjectToIntegerConvert());
Set<Entry<String, Convert<?,?>>> entites = convertHandlers.entrySet();
StringBuilder b = new StringBuilder();
b.append("{");
for(Entry<String, Convert<?,?>> entry: entites){
b.append(entry.getKey()).append("=").append(entry.getValue()).append(",");
}
b.append("}");
log.debug("all support convert type: "+b.toString().replaceFirst(",}", "}"));
}
@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T> T convert(Class<T> clazz,Object val){
Convert cv = convertHandlers.get(val.getClass().getName()+"To"+clazz.getName());
if(cv == null){
log.info(clazz.getName()+"To"+val.getClass().getName()+ " convert failed: unsupport type");
return null;
}
return (T)cv.convert(val);
}
}
下面贴出来各种转换实现类：
import org.apache.commons.logging.LogFactory;
public class ObjectArrToDoublArrConvert implements Convert<Object[],double[]> {
@Override
public double[] convert(Object[] source) {
if(source == null) return null;
double[] res = new double[source.length];
for(int i=0;i<source.length;i++){
try {
res[i] = Double.parseDouble(source[i].toString());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectArrToDoublArrConvert failed, bad value: "+source[i].toString(), e);
return null;
}
}
return res;
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectArrToDoubleArrConvert implements Convert<Object[],Double[]> {
@Override
public Double[] convert(Object[] source) {
if(source == null) return null;
Double[] res = new Double[source.length];
for(int i=0;i<source.length;i++){
try {
res[i] = Double.parseDouble(source[i].toString());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectArrToDoubleArrConvert failed, bad value: "+source[i].toString(), e);
return null;
}
}
return res;
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectArrToFloaArrConvert implements Convert<Object[],float[]> {
@Override
public float[] convert(Object[] source) {
if(source == null) return null;
float[] res = new float[source.length];
for(int i=0;i<source.length;i++){
try {
res[i] = Float.parseFloat(source[i].toString());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectArrToFloaArrConvert failed, bad value: "+source[i].toString(), e);
return null;
}
}
return res;
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectArrToFloatArrConvert implements Convert<Object[],Float[]> {
@Override
public Float[] convert(Object[] source) {
if(source == null) return null;
Float[] res = new Float[source.length];
for(int i=0;i<source.length;i++){
try {
res[i] = Float.parseFloat(source[i].toString());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectArrToFloatArrConvert failed, bad value: "+source[i].toString(), e);
return null;
}
}
return res;
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectArrToIntArrConvert implements Convert<Object[],int[]> {
@Override
public int[] convert(Object[] source) {
if(source == null) return null;
int[] res = new int[source.length];
for(int i=0;i<source.length;i++){
try {
res[i] = Integer.parseInt(source[i].toString());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectArrToIntArrConvert failed, bad value: "+source[i].toString(), e);
return null;
}
}
return res;
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectArrToIntegerArrConvert implements Convert<Object[],Integer[]> {
@Override
public Integer[] convert(Object[] source) {
if(source == null) return null;
Integer[] res = new Integer[source.length];
for(int i=0;i<source.length;i++){
try {
res[i] = Integer.parseInt(source[i].toString());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectArrToIntegerArrConvert failed, bad value: "+source[i].toString(), e);
return null;
}
}
return res;
}
}
public class ObjectArrToStringArrConvert implements Convert<Object[],String[]> {
@Override
public String[] convert(Object[] source) {
if(source == null) return null;
String[] res = new String[source.length];
for(int i=0;i<source.length;i++){
res[i] = source[i].toString();
}
return res;
}
}
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.regex.Pattern;
import org.apache.commons.logging.LogFactory;
/**
*支持的日期格式为：<br>
*yyyy-MM-dd<br>
*yyyy-MM-dd HH:mm<br>
*yyyy-MM-dd HH:mm:ss<br>
*yyyy/MM/dd<br>
*yyyy/MM/dd HH:mm<br>
*yyyy/MM/dd HH:mm:ss<br>
*/
public class ObjectToDateConvert implements Convert<Object,Date> {
Object[][] patterns = {
{Pattern.compile("^\\d+-\\d+-\\d+$"),"yyyy-MM-dd"},
{Pattern.compile("^\\d+-\\d+-\\d+ \\d+:\\d+$"),"yyyy-MM-dd HH:mm"},
{Pattern.compile("^\\d+-\\d+-\\d+ \\d+:\\d+:\\d+$"),"yyyy-MM-dd HH:mm:ss"},
{Pattern.compile("^\\d+/\\d+/\\d+$"),"yyyy/MM/dd"},
{Pattern.compile("^\\d+/\\d+/\\d+ \\d+:\\d+$"),"yyyy/MM/dd HH:mm"},
{Pattern.compile("^\\d+/\\d+/\\d+ \\d+:\\d+:\\d+$"),"yyyy/MM/dd HH:mm:ss"}
};
@Override
public Date convert(Object source) {
if(source == null) return null;
String val = source.toString();
val = val.trim();
String format = null;
Pattern p;
for(Object[] item:patterns){
p = (Pattern)item[0];
if(p.matcher(val).matches()){
format = item[1].toString();
break;
}
}
if(format == null) {
LogFactory.getLog(getClass()).info("ObjectToDateConvert failed, unsupport value: "+source);
return null;
}
try {
return new SimpleDateFormat(format).parse(val);
} catch (ParseException e) {
LogFactory.getLog(getClass()).info("ObjectToDateConvert failed, bad value: "+source,e);
return null;
}
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectToFloatConvert implements Convert<Object,Float> {
@Override
public Float convert(Object source) {
if(source == null) return null;
try {
return Float.parseFloat(source.toString().trim());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectToFloatConvert failed: "+source, e);
return null;
}
}
}
import org.apache.commons.logging.LogFactory;
public class ObjectToIntegerConvert implements Convert<Object,Integer> {
@Override
public Integer convert(Object source) {
if(source == null) return null;
try {
return Integer.parseInt(source.toString().trim());
} catch (NumberFormatException e) {
LogFactory.getLog(getClass()).info("ObjectToIntegerConvert failed: "+source, e);
return null;
}
}
}
使用方法如下：
Map<String,Object> map = new HashMap<String, Object>();
map.put("intVal", "1");
map.put("integerVal", "1");
map.put("floatVal", "1.0");
map.put("doubleVal", "1.0");
map.put("dateVal", "2012-12-12 23:00:00");
map.put("intArr", new String[]{"1","2"});
map.put("integerArr", new String[]{"1","2"});
map.put("strArr", new String[]{"A","B"});
map.put("floatArr", new String[]{"1.0","1.0"});
MapToEntryConvertUtils.convert(map, TestEntry.class, "");
MapToEntryConvertUtils.convert(map, TestEntry.class, "");
第一次转换比较慢，但是第二次因为缓存了类的属性信息所以很快