java集合中尋找指定對象的集合或對象數據


package com.xiniunet.web.tool;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
* Created by xn on 15/7/22.
*/
public class ListUtil {

/**
* 判斷集合中是否存在該對象的數據
* @param list
* @param value
* @param <T>
* @return 返回在集合中首次匹配到的對象數據
*/
public static <T> T matchObject(List<T> list,T value) {
if(list == null || list.size() == 0 || value == null){
return null;
}
for(T t : list) {
if(value.equals(t)){
return t;
}
}
return null;
}

/**
* 判斷集合中是否存在該長整型數值的數據對象
* @param list
* @param id
* @param <T>
* @return 返回首次符合長整型數值的數據對象
*/
public static <T> T matchObject(List<T> list,Long id) {
if(list == null || list.size() == 0 || id == null){
return null;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("getId");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
for(T t : list) {
try {
if(id.equals(method.invoke(t))){
return t;
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
return null;
}

/**
* 判斷集合中是否存在該長整型數值的數據對象
* @param list
* @param id
* @param <T>
* @return 返回符合長整型數值的數據集合對象
*/
public static <T> List<T> matchList(List<T> list,Long id) {

List<T> result = new ArrayList();
if(list == null || list.size() == 0 || id == null){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("getId");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}

for(T t : list) {
try {
if(id.equals(method.invoke(t))){
result.add(t);
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
return result;
}

/**
* 判斷集合中是否存在該長整型數據集合的集合數據
* @param list
* @param ids
* @param <T>
* @return 返回符合長整型數值的數據集合對象
*/
public static <T> List<T> matchList(List<T> list,List<Long> ids) {

List<T> result = new ArrayList();
if(list == null || list.size() == 0 || ids == null || ids.size() == 0){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("getId");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}

for(Long id : ids){
for(T t : list) {
try {
if(id.equals(method.invoke(t))){
result.add(t);
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
}

return result;
}

/**
* 循環判斷集合中是否存在長整型數據集合中的數據(每個對象只匹配第一次取到的值)
* @param list
* @param ids
* @param <T>
* @return 返回符合長整型數據集合中的集合對象(每個對象只匹配第一次取到的值)
*/
public static <T> List<T> matchBatchObject(List<T> list,List<Long> ids) {

List<T> result = new ArrayList();
if(list == null || list.size() == 0 || ids == null || ids.size() == 0){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("getId");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
for(Long id :ids){
for(T t : list) {
try {
if(id.equals(method.invoke(t))){
result.add(t);
break;
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
}
return result;
}

/**
* 判斷集合中是否存在該對象相匹配的對象數據
* @param list
* @param fieldName
* @param id
* @param <T>
* @param <K>
* @return 返回符合對象相匹配的對象數據
*/
public static <T,K> T matchObject(List<T> list,String fieldName,K id) {
if(list == null || list.size() == 0 || id == null){
return null;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("get" + Character.isUpperCase(fieldName.charAt(0)));
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
for(T t : list) {
try {
if(id.equals(method.invoke(t))){
return t;
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
return null;
}

/**
* 判斷集合中是否存在該對象相匹配的對象數據
* @param list
* @param fieldName
* @param id
* @param <T>
* @param <K>
* @return 返回符合對象相匹配的集合對象
*/
public static <T,K> List<T> matchList(List<T> list,String fieldName,K id) {

List<T> result = new ArrayList();
if(list == null || list.size() == 0 || id == null){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("get" + Character.isUpperCase(fieldName.charAt(0)));
} catch (NoSuchMethodException e) {
e.printStackTrace();
}

for(T t : list) {
try {
if(id.equals(method.invoke(t))){
result.add(t);
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
return result;
}

/**
* 循環判斷集合中是否存在該對象相匹配的對象數據
* @param list
* @param fieldName
* @param ids
* @param <T>
* @param <K>
* @return 返回符合對象相匹配的集合對象
*/
public static <T,K> List<T> matchList(List<T> list,String fieldName,List<K> ids) {

List<T> result = new ArrayList();
if(list == null || list.size() == 0 || ids == null || ids.size() == 0){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("get" + Character.isUpperCase(fieldName.charAt(0)));
} catch (NoSuchMethodException e) {
e.printStackTrace();
}

for(K id : ids){
for(T t : list) {
try {
if(id.equals(method.invoke(t))){
result.add(t);
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
}
return result;
}

/**
* 判斷集合中是否存在該對象相匹配的對象數據(每個對象只匹配第一次取到的值)
* @param list
* @param fieldName
* @param ids
* @param <T>
* @param <K>
* @return 返回符合對象相匹配的集合對象(每個對象只匹配第一次取到的值)
*/
public static <T,K> List<T> matchBatchObject(List<T> list,String fieldName,List<K> ids) {

List<T> result = new ArrayList();
if(list == null || list.size() == 0 || ids == null || ids.size() == 0){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("get" + Character.isUpperCase(fieldName.charAt(0)));
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
for(K id :ids){
for(T t : list) {
try {
if(id.equals(method.invoke(t))){
result.add(t);
break;
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
}
return result;
}

public static <T> List<Long> getKeyList(List<T> list) {

List<Long> result = new ArrayList();
if(list == null || list.size() == 0){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("getId");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}

Set<Long> set = new HashSet<>();
for(T t : list) {
try {
Long id = (Long)method.invoke(t);
if(id != null){
set.add(id);
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
for(Long id : set){
result.add(id);
}
return result;
}

public static <T,K> List<K> getKeyList(List<T> list,String fieldName) {

List<K> result = new ArrayList();
if(list == null || list.size() == 0){
return result;
}
Class clazz = list.get(0).getClass();
Method method = null;
try {
method = clazz.getMethod("get" + Character.isUpperCase(fieldName.charAt(0)));
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
Set<K> set = new HashSet<>();

for(T t : list) {
try {
K k = (K)method.invoke(t);
if(k != null){
set.add(k);
}
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
for(K k : set){
result.add(k);
}
return result;
}
}


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