实现的原因
Spring中的BeanUtils.copyProperties(source,target),不能忽略大小写，类型不同不能相互赋值。速度并不是特别理想。自己根据反射实现了工具类。 其中ReflectASM需要引入下面jar包
<!---RelectAsm-->
<dependency>
<groupId>com.esotericsoftware</groupId>
<artifactId>reflectasm</artifactId>
<version>1.11.7</version>
</dependency>
#具体代码
import com.esotericsoftware.reflectasm.MethodAccess;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.*;
/**
*
* @Auther: xjw
* @Description: 此类主要用于反射，对反射的一些操作进行缓存起来。
*/
public class BeanUtils {
/**
* 集合 copy
*
* @param sources
* @param target
* @param <T>
* @return
*/
public static <T> List<T> listCopyPropertiesASM(List sources, Class<T> target) {
List list = new ArrayList<>(sources.size());
sources.forEach(it -> {
list.add(copyPropertiesASM(it, target));
});
return list;
}
/**
* 通过 target的Class 复制
* target 必须有一个无参构造器
*
* @param source
* @param target
* @param <T>
* @return
*/
public static <T> T copyPropertiesASM(Object source, Class<T> target) {
T newT = null;
try {
newT = target.newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return copyPropertiesASM(source, newT);
}
/**
* 通过 ASM反射 速度比 Spring BeanUtils.copyProperties(source,target) 快一倍
* 大小写可以忽略
* 下划线 _ 被忽略
*
* @param source 源对象
* @param target 目标实例化对象
* @param <T>
* @return
*/
public static <T> T copyPropertiesASM(Object source, Object target) {
MethodAccess sourceMethodAccess = CacheMethodAccess.getMethodAccess(source.getClass());
MethodAccess targetMethodAccess = CacheMethodAccess.getMethodAccess(target.getClass());
Map<String, String> sourceGet = CacheAsmFiledMethod.getMethod("get", source.getClass());
Map<String, String> targetSet = CacheAsmFiledMethod.getMethod("set", target.getClass());
CacheFieldMap.getFieldMap(target.getClass()).keySet().forEach((it) -> {
String sourceIndex = sourceGet.get(it);
if (sourceIndex != null) {
Object value = sourceMethodAccess.invoke(source, sourceIndex);
String setIndex = targetSet.get(it);
targetMethodAccess.invoke(target, setIndex, value);
}
});
return (T) target;
}
/**
* 模仿Spring中 BeanUtils.copyProperties(source,target)
* 大小写可以忽略
* 下划线 _ 被忽略
*
* @param source
* @param target
* @param <T>
* @return
*/
public static <T> T copyProperties(Object source, Object target) {
Map<String, Field> sourceMap = CacheFieldMap.getFieldMap(source.getClass());
CacheFieldMap.getFieldMap(target.getClass()).values().forEach((it) -> {
Field field = sourceMap.get(it.getName().toLowerCase().replace("_", ""));
if (field != null) {
it.setAccessible(true);
field.setAccessible(true);
try {
it.set(target, field.get(source));
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
});
return (T) target;
}
private static class CacheAsmFiledMethod {
private static Map<String, Map<String, String>> cacheGetMethod = new HashMap<>();
private static Map<String, Map<String, String>> cacheSetMethod = new HashMap<>();
private static Map<String, String> getMethod(String type, Class clazz) {
MethodAccess methodAccess = CacheMethodAccess.getMethodAccess(clazz);
Map<String, Field> allFields = CacheFieldMap.getFieldMap(clazz);
Map<String, String> result = null;
if (type.equals("get")) {
result = cacheGetMethod.get(clazz.getName());
} else if (type.equals("set")) {
result = cacheSetMethod.get(clazz.getName());
}
if (result == null) {
synchronized (CacheAsmFiledMethod.class) {
if (result == null) {
Map<String, String> set = new HashMap<>();
Map<String, String> get = new HashMap<>();
allFields.values().forEach((it) -> {
//判断是否是静态
if (!Modifier.isStatic(it.getModifiers())) {
//首字母大写
char[] f = it.getName().toCharArray();
f[0] -= 32;
String fieldName = new String(f);
get.put(fieldName.toLowerCase().replace("_", ""), "get" + fieldName);
set.put(fieldName.toLowerCase().replace("_", ""), "set" + fieldName);
}
});
cacheGetMethod.put(clazz.getName(), get);
cacheSetMethod.put(clazz.getName(), set);
if (type.equals("get")) {
result = cacheGetMethod.get(clazz.getName());
} else if (type.equals("set")) {
result = cacheSetMethod.get(clazz.getName());
}
}
}
}
return result;
}
}
private static class SingelClass {
private static Map<String, Object> cacheObject = new HashMap<>();
private SingelClass() {
}
private static <T> T getObject(Class<T> clazz) {
T result = (T) cacheObject.get(clazz.getName());
if (result == null) {
synchronized (SingelClass.class) {
if (result == null) {
try {
cacheObject.put(clazz.getName(), clazz.newInstance());
result = (T) cacheObject.get(clazz.getName());
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
return result;
}
}
private static class CacheMethodAccess {
private CacheMethodAccess() {
}
private static Map<String, MethodAccess> cache = new HashMap<>();
private static MethodAccess getMethodAccess(Class clazz) {
MethodAccess result = cache.get(clazz.getName());
if (result == null) {
synchronized (CacheMethodAccess.class) {
if (result == null) {
cache.put(clazz.getName(), MethodAccess.get(clazz));
result = cache.get(clazz.getName());
}
}
}
return result;
}
}
private static class CacheFieldMap {
private static Map<String, Map<String, Field>> cacheMap = new HashMap<>();
private static Map<String, Field> getFieldMap(Class clazz) {
Map<String, Field> result = cacheMap.get(clazz.getName());
if (result == null) {
synchronized (CacheFieldMap.class) {
if (result == null) {
Map<String, Field> fieldMap = new HashMap<>();
for (Field field : clazz.getDeclaredFields()) {
fieldMap.put(field.getName().toLowerCase().replace("_", ""), field);
}
cacheMap.put(clazz.getName(), fieldMap);
result = cacheMap.get(clazz.getName());
}
}
}
return result;
}
}
}
测试
public static void main(String[] args) {
Man man = new Man("name", 20);
Woman woman = BeanUtils.copyPropertiesASM(man, Woman.class);
System.out.println(woman);
List<Man> manList = new ArrayList<>();
for (int i = 0; i < 100; i++) {
manList.add(new Man("name" + i, i));
}
List<Woman> womens = BeanUtils.listCopyPropertiesASM(manList,Woman.class);
System.out.println(womens);
}