我有两个不同类型的员工和贷款列表
List<CsvVo> csv1Records = CsvParser.getRecodrsFromACsv(csv1, csv1Headers, "employee");
List<CsvVo> csv2Records = CsvParser.getRecodrsFromACsv(csv2, csv2Headers, "loan");
我想知道 csv1Records 列表中是否存在与 csv2Records 贷款列表中具有相同 empid 的员工。
这是我对此的最佳尝试之一，
List<OutputData> result = csv1Records.stream().flatMap(x -> csv2Records.stream().filter(y -> x.get(CsvParser.key1).getProprieties().get("empid").equals(y.get(CsvParser.key2).getProprieties2().get("empid"))).map(y -> new OutputData(x.get(CsvParser.key1).getNameOfEmployee(),
x.get(CsvParser.key1).getProprieties(),
y.get(CsvParser.key2).getNameOfLoan(),
y.get(CsvParser.key2).getProprieties2()))).collect(Collectors.toList());
mergingresults.csv 中的结果如下:
nameOfEmployee,proprieties,nameOfLoan,proprieties
Kevin,{"empid":1,"age":50,"education":"abc college"},pc,{"loan":4777.00,"balance":280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},home,{"loan":140000.00,"balance":60080.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},kitchen,{"loan":4000.00,"balance":3280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},car,{"loan":140000.00,"balance":60080.0,"empid":1}
Carole,{"empid":2,"age":25,"education":"koala college"},health,{"loan":1400,"balance":2800.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},trip,{"loan":14000.00,"balance":6080.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},food,{"loan":400.00,"balance":328.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},education,{"loan":14000.00,"balance":60080.0,"empid":2}
上面的结果与我想要的和我的需求不同，如下所述:
nameOfEmployee,proprieties,nameOfLoan,proprieties
Kevin,{"empid":1,"age":50,"education":"abc college"},pc,{"loan":4777.00,"balance":280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},home,{"loan":140000.00,"balance":60080.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},kitchen,{"loan":4000.00,"balance":3280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},car,{"loan":140000.00,"balance":60080.0,"empid":1}
Carole,{"empid":2,"age":25,"education":"koala college"},health,{"loan":1400,"balance":2800.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},trip,{"loan":14000.00,"balance":6080.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},food,{"loan":400.00,"balance":328.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},education,{"loan":14000.00,"balance":60080.0,"empid":2}
Sebastian,{"empid":3,"age":47,"education":"Rubbits college"},null,null
Daniel,{"empid":4,"age":30,"education":"Pencil college"},null,null
David,{"empid":5,"age":20,"education":"Kodi college"},null,null
Michael,{"empid":6,"age":19,"education":"red college"},null,null
Alain,{"empid":7,"age":35,"education":"green college"},null,null
Rachel,{"empid":8,"age":55,"education":"white college"},null,null
有关更多信息、完整说明和完整代码，请参阅下文
我有两个 csv 文件employee.csv 和loan.csv。
在employee.csv中我有两列，即
nameOfEmployee(String)
{"empid":empid(Integer),"age": age(Integer),"education": "education(String)"}
注意:第二列作为 json 属性列。
在loan.csv中我有两列，即
nameOfLoan(String)
{"loan":loan(Double),"balance":balance(Double),"empid":empid(Integer)}
注意:第二列作为 json 属性列
现在，我想通过 empid json 属性列将这两个 csv 文件合并为一个 csv 文件。
因此，在 mergingresults.csv 文件中，4 列应如下所示，
nameOfEmployee(String)
{"empid":empid(Integer),"age": age(Integer),"education": "education(String)"},nameOfLoan(String),{"loan":loan(Double),"balance":balance(Double),"empid":empid(Integer)}
一个 nameOfEmployee 可能与多个 nameOfLoans 相关。
我只能通过使用 java 流使用纯 java-8 来实现这一点。 有人可以帮我吗？
例如员工.csv:
nameOfEmployee,proprieties
Kevin,{"empid":1,"age":50,"education":"abc college"}
Carole,{"empid":2,"age":25,"education":"koala college"}
Sebastian,{"empid":3,"age":47,"education":"Rubbits college"}
Daniel,{"empid":4,"age":30,"education":"Pencil college"}
David,{"empid":5,"age":20,"education":"Kodi college"}
Michael,{"empid":6,"age":19,"education":"red college"}
Alain,{"empid":7,"age":35,"education":"green college"}
Rachel,{"empid":8,"age":55,"education":"white college"}
贷款.csv
nameOfLoan,proprieties
pc,{"loan":4777.00,"balance":280.0,"empid":1}
home,{"loan":140000.00,"balance":60080.0,"empid":1}
kitchen,{"loan":4000.00,"balance":3280.0,"empid":1}
car,{"loan":140000.00,"balance":60080.0,"empid":1}
health,{"loan":1400,"balance":2800.0,"empid":2}
trip,{"loan":14000.00,"balance":6080.0,"empid":2}
food,{"loan":400.00,"balance":328.0,"empid":2}
education,{"loan":14000.00,"balance":60080.0,"empid":2}
所需的 results.csv 应如下所示:
nameOfEmployee,proprieties,nameOfLoan,proprieties
Kevin,{"empid":1,"age":50,"education":"abc college"},pc,{"loan":4777.00,"balance":280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},home,{"loan":140000.00,"balance":60080.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},kitchen,{"loan":4000.00,"balance":3280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},car,{"loan":140000.00,"balance":60080.0,"empid":1}
Carole,{"empid":2,"age":25,"education":"koala college"},health,{"loan":1400,"balance":2800.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},trip,{"loan":14000.00,"balance":6080.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},food,{"loan":400.00,"balance":328.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},education,{"loan":14000.00,"balance":60080.0,"empid":2}
Sebastian,{"empid":3,"age":47,"education":"Rubbits college"},null,null
Daniel,{"empid":4,"age":30,"education":"Pencil college"},null,null
David,{"empid":5,"age":20,"education":"Kodi college"},null,null
Michael,{"empid":6,"age":19,"education":"red college"},null,null
Alain,{"empid":7,"age":35,"education":"green college"},null,null
Rachel,{"empid":8,"age":55,"education":"white college"},null,null
注意:最后六行空值不存在于我的 result.csv 中(两个 csv 的合并应该像两个列表的左连接一样)。
完整代码MergeCSVs.java
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
class OutputData {
public OutputData(String nameOfEmployee, JsonObject proprieties, String nameOfLoan, JsonObject proprieties2) {
super();
this.nameOfEmployee = nameOfEmployee;
this.proprieties = proprieties;
this.nameOfLoan = nameOfLoan;
this.proprieties2 = proprieties2;
}
public String getNameOfEmployee() {
return nameOfEmployee;
}
public void setNameOfEmployee(String nameOfEmployee) {
this.nameOfEmployee = nameOfEmployee;
}
public JsonObject getProprieties() {
return proprieties;
}
public void setProprieties(JsonObject proprieties) {
this.proprieties = proprieties;
}
public String getNameOfLoan() {
return nameOfLoan;
}
public void setNameOfLoan(String nameOfLoan) {
this.nameOfLoan = nameOfLoan;
}
public JsonObject getProprieties2() {
return proprieties2;
}
public void setProprieties2(JsonObject proprieties2) {
this.proprieties2 = proprieties2;
}
private String nameOfEmployee;
private JsonObject proprieties;
private String nameOfLoan;
private JsonObject proprieties2;
}
class Loan {
public Loan(String nameOfLoan, JsonObject proprieties2) {
super();
this.nameOfLoan = nameOfLoan;
this.proprieties2 = proprieties2;
}
public String getNameOfLoan() {
return nameOfLoan;
}
public void setNameOfLoan(String nameOfLoan) {
this.nameOfLoan = nameOfLoan;
}
public JsonObject getProprieties2() {
return proprieties2;
}
public void setProprieties2(JsonObject proprieties2) {
this.proprieties2 = proprieties2;
}
private String nameOfLoan;
private JsonObject proprieties2;
}
class Employee {
public Employee(String nameOfEmployee, JsonObject proprieties) {
super();
this.nameOfEmployee = nameOfEmployee;
this.proprieties = proprieties;
}
public String getNameOfEmployee() {
return nameOfEmployee;
}
public void setNameOfEmployee(String nameOfEmployee) {
this.nameOfEmployee = nameOfEmployee;
}
public JsonObject getProprieties() {
return proprieties;
}
public void setProprieties(JsonObject proprieties) {
this.proprieties = proprieties;
}
private String nameOfEmployee;
private JsonObject proprieties;
}
class Key<T> {
final String identifier;
final Class<T> type;
public Key(String identifier, Class<T> type) {
this.identifier = identifier;
this.type = type;
}
public static <T> Key<T> key(String identifier, Class<T> type) {
return new Key<>(identifier, type);
}
}
class CsvVo {
private final Map<Key<?>, Object> keyVal;
public CsvVo(String id) {
keyVal = new LinkedHashMap<>();// you may also use HashMap if you don't need
// to keep order
}
public <T> void put(Key<T> key, T value) {
keyVal.put(key, value);
}
public <T> T get(Key<T> key) {
return key.type.cast(keyVal.get(key));
}
}
class CsvParser {
public static Key<Employee> key1 = new Key<>("id1", Employee.class);
public static Key<Loan> key2 = new Key<>("id2", Loan.class);
public static List<CsvVo> getRecodrsFromACsv(File file, List<String> keys, String name) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(file));
List<CsvVo> records = new ArrayList<>();
boolean isHeader = true;
String line = null;
while((line = br.readLine()) != null) {
if(isHeader) {// first line is header
isHeader = false;
continue;
}
CsvVo record = new CsvVo(file.getName());
if(name == "employee") {
String[] lineSplit = line.split(",", 2);
Employee employee = new Employee(lineSplit[0], new JsonParser().parse(lineSplit[1]).getAsJsonObject());
record.put(key1, employee);
}
else {
String[] lineSplit = line.split(",", 2);
Loan loan = new Loan(lineSplit[0], new JsonParser().parse(lineSplit[1]).getAsJsonObject());
record.put(key2, loan);
}
records.add(record);
}
br.close();
return records;
}
public static List<String> getHeadersFromACsv(File file) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(file));
List<String> headers = null;
String line = null;
while((line = br.readLine()) != null) {
String[] lineSplit = line.split(",");
headers = new ArrayList<>(Arrays.asList(lineSplit));
break;
}
br.close();
return headers;
}
public static void writeToCsv(final File file,
final Set<String> headers,
final List<OutputData> records) throws IOException {
FileWriter csvWriter = new FileWriter(file);
// write headers
String sep = "";
String[] headersArr = headers.toArray(new String[headers.size()]);
for(String header : headersArr) {
csvWriter.append(sep);
csvWriter.append(header);
sep = ",";
}
csvWriter.append("\n");
// write records at each line
for(OutputData record : records) {
sep = "";
for(int i = 0; i < headersArr.length; i++) {
csvWriter.append(sep);
String s = headersArr[i];
if(s.equalsIgnoreCase("nameOfEmployee")) {
csvWriter.append(record.getNameOfEmployee().toString());
}
else if(s.equalsIgnoreCase("proprieties")) {
csvWriter.append(record.getProprieties().toString());
}
else if(s.equalsIgnoreCase("nameOfLoan")) {
csvWriter.append(record.getNameOfLoan().toString());
}
else if(s.equalsIgnoreCase("proprieties2")) {
csvWriter.append(record.getProprieties2().toString());
}
sep = ",";
}
csvWriter.append("\n");
}
csvWriter.flush();
csvWriter.close();
}
}
public class MergeCSVs {
public static void main(String[] args) throws IOException {
String fullpath = System.getProperty("user.dir") + "/" + "employee.csv";
String fullpath2 = System.getProperty("user.dir") + "/" + "loan.csv";
File csv1 = new File(fullpath);
File csv2 = new File(fullpath2);
List<String> csv1Headers = CsvParser.getHeadersFromACsv(csv1);
// csv1Headers.forEach(h -> System.out.print(h + " "));
// System.out.println();
List<String> csv2Headers = CsvParser.getHeadersFromACsv(csv2);
// csv2Headers.forEach(h -> System.out.print(h + " "));
// System.out.println();
List<String> allCsvHeaders = new ArrayList<>();
allCsvHeaders.addAll(csv1Headers);
allCsvHeaders.addAll(csv2Headers);
// allCsvHeaders.forEach(h -> System.out.print(h + " "));
// System.out.println();
Set<String> uniqueHeaders = new LinkedHashSet<>(allCsvHeaders);
// uniqueHeaders.forEach(h -> System.out.print(h + " "));
// System.out.println();
List<CsvVo> csv1Records = CsvParser.getRecodrsFromACsv(csv1, csv1Headers, "employee");
List<CsvVo> csv2Records = CsvParser.getRecodrsFromACsv(csv2, csv2Headers, "loan");
List<OutputData> result = csv1Records.stream().flatMap(x -> csv2Records.stream().filter(y -> x.get(CsvParser.key1).getProprieties().get("empid").equals(y.get(CsvParser.key2).getProprieties2().get("empid"))).map(y -> new OutputData(x.get(CsvParser.key1).getNameOfEmployee(),
x.get(CsvParser.key1).getProprieties(),
y.get(CsvParser.key2).getNameOfLoan(),
y.get(CsvParser.key2).getProprieties2()))).collect(Collectors.toList());
List<OutputData> allCsvRecords = new ArrayList<>();
allCsvRecords.addAll(result);
String fullpath3 = System.getProperty("user.dir") + "/" + "mergingresults.csv";
CsvParser.writeToCsv(new File(fullpath3), uniqueHeaders, allCsvRecords);
}
}
非常感谢。
最佳答案
这是一种可能对其他人将来有帮助的解决方案。
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import com.google.common.base.Supplier;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Multimap;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
class MultimapCollector<T, K, V> implements Collector<T, Multimap<K, V>, Multimap<K, V>> {
private final Function<T, K> keyGetter;
private final Function<T, V> valueGetter;
public MultimapCollector(Function<T, K> keyGetter, Function<T, V> valueGetter) {
this.keyGetter = keyGetter;
this.valueGetter = valueGetter;
}
public static <T, K, V> MultimapCollector<T, K, V> toMultimap(Function<T, K> keyGetter, Function<T, V> valueGetter) {
return new MultimapCollector<>(keyGetter, valueGetter);
}
public static <T, K, V> MultimapCollector<T, K, T> toMultimap(Function<T, K> keyGetter) {
return new MultimapCollector<>(keyGetter, v -> v);
}
@Override
public Supplier<Multimap<K, V>> supplier() {
return ArrayListMultimap::create;
}
@Override
public BiConsumer<Multimap<K, V>, T> accumulator() {
return (map, element) -> map.put(keyGetter.apply(element), valueGetter.apply(element));
}
@Override
public BinaryOperator<Multimap<K, V>> combiner() {
return (map1, map2) -> {
map1.putAll(map2);
return map1;
};
}
@Override
public Function<Multimap<K, V>, Multimap<K, V>> finisher() {
return map -> map;
}
@Override
public Set<Characteristics> characteristics() {
return ImmutableSet.of(Characteristics.IDENTITY_FINISH);
}
}
class OutputData {
public OutputData(String nameOfEmployee, JsonObject proprieties, String nameOfLoan, JsonObject proprieties2) {
super();
this.nameOfEmployee = nameOfEmployee;
this.proprieties = proprieties;
this.nameOfLoan = nameOfLoan;
this.proprieties2 = proprieties2;
}
public String getNameOfEmployee() {
return nameOfEmployee;
}
public void setNameOfEmployee(String nameOfEmployee) {
this.nameOfEmployee = nameOfEmployee;
}
public JsonObject getProprieties() {
return proprieties;
}
public void setProprieties(JsonObject proprieties) {
this.proprieties = proprieties;
}
public String getNameOfLoan() {
return nameOfLoan;
}
public void setNameOfLoan(String nameOfLoan) {
this.nameOfLoan = nameOfLoan;
}
public JsonObject getProprieties2() {
return proprieties2;
}
public void setProprieties2(JsonObject proprieties2) {
this.proprieties2 = proprieties2;
}
private String nameOfEmployee;
private JsonObject proprieties;
private String nameOfLoan;
private JsonObject proprieties2;
}
class Loan {
public Loan(String nameOfLoan, JsonObject proprieties2) {
super();
this.nameOfLoan = nameOfLoan;
this.proprieties2 = proprieties2;
}
public String getNameOfLoan() {
return nameOfLoan;
}
public void setNameOfLoan(String nameOfLoan) {
this.nameOfLoan = nameOfLoan;
}
public JsonObject getProprieties2() {
return proprieties2;
}
public void setProprieties2(JsonObject proprieties2) {
this.proprieties2 = proprieties2;
}
private String nameOfLoan;
private JsonObject proprieties2;
private String loanId;
public String getLoanId() {
String el = this.proprieties2.get("empid").toString();
return el;
}
public void setLoanId(String loanId) {
this.loanId = loanId;
}
}
class Employee {
public Employee(String nameOfEmployee, JsonObject proprieties) {
super();
this.nameOfEmployee = nameOfEmployee;
this.proprieties = proprieties;
}
public String getNameOfEmployee() {
return nameOfEmployee;
}
public void setNameOfEmployee(String nameOfEmployee) {
this.nameOfEmployee = nameOfEmployee;
}
public JsonObject getProprieties() {
return proprieties;
}
public void setProprieties(JsonObject proprieties) {
this.proprieties = proprieties;
}
private String employeeId;
public String getEmployeeId() {
String el = this.proprieties.get("empid").toString();
return el;
}
public void setEmployeeId(String employeeId) {
this.employeeId = employeeId;
}
private String nameOfEmployee;
private JsonObject proprieties;
}
class Key<T> {
final String identifier;
final Class<T> type;
public Key(String identifier, Class<T> type) {
this.identifier = identifier;
this.type = type;
}
public static <T> Key<T> key(String identifier, Class<T> type) {
return new Key<>(identifier, type);
}
}
class CsvVo {
private final Map<Key<?>, Object> keyVal;
public CsvVo(String id) {
keyVal = new LinkedHashMap<>();// you may also use HashMap if you don't need
// to keep order
}
public <T> void put(Key<T> key, T value) {
keyVal.put(key, value);
}
public <T> T get(Key<T> key) {
return key.type.cast(keyVal.get(key));
}
}
class CsvParser {
public static Key<Employee> key1 = new Key<>("id1", Employee.class);
public static Key<Loan> key2 = new Key<>("id2", Loan.class);
public static List<CsvVo> getRecodrsFromACsv(File file, List<String> keys, String name) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(file));
List<CsvVo> records = new ArrayList<>();
boolean isHeader = true;
String line = null;
while((line = br.readLine()) != null) {
if(isHeader) {// first line is header
isHeader = false;
continue;
}
CsvVo record = new CsvVo(file.getName());
if(name == "employee") {
String[] lineSplit = line.split(",", 2);
Employee employee = new Employee(lineSplit[0], new JsonParser().parse(lineSplit[1]).getAsJsonObject());
record.put(key1, employee);
}
else {
String[] lineSplit = line.split(",", 2);
Loan loan = new Loan(lineSplit[0], new JsonParser().parse(lineSplit[1]).getAsJsonObject());
record.put(key2, loan);
}
records.add(record);
}
br.close();
return records;
}
public static List<String> getHeadersFromACsv(File file) throws IOException {
BufferedReader br = new BufferedReader(new FileReader(file));
List<String> headers = null;
String line = null;
while((line = br.readLine()) != null) {
String[] lineSplit = line.split(",");
headers = new ArrayList<>(Arrays.asList(lineSplit));
break;
}
br.close();
return headers;
}
public static void writeToCsv(final File file,
final Set<String> headers,
final List<OutputData> records) throws IOException {
FileWriter csvWriter = new FileWriter(file);
// write headers
String sep = "";
String[] headersArr = headers.toArray(new String[headers.size()]);
for(String header : headersArr) {
csvWriter.append(sep);
csvWriter.append(header);
sep = ",";
}
csvWriter.append("\n");
// write records at each line
for(OutputData record : records) {
sep = "";
for(int i = 0; i < headersArr.length; i++) {
csvWriter.append(sep);
String s = headersArr[i];
if(s.equalsIgnoreCase("nameOfEmployee")) {
csvWriter.append(record.getNameOfEmployee().toString());
}
else if(s.equalsIgnoreCase("proprieties")) {
csvWriter.append(record.getProprieties().toString());
}
else if(s.equalsIgnoreCase("nameOfLoan")) {
if(record.getNameOfLoan() != null)
csvWriter.append(record.getNameOfLoan().toString());
else
csvWriter.append("null");
}
else if(s.equalsIgnoreCase("proprieties2")) {
if(record.getProprieties2() != null)
csvWriter.append(record.getProprieties2().toString());
else
csvWriter.append("null");
}
sep = ",";
}
csvWriter.append("\n");
}
csvWriter.flush();
csvWriter.close();
}
}
public class MergeCSVs {
public static void main(String[] args) throws IOException {
String fullpath = System.getProperty("user.dir") + "/" + "employee.csv";
String fullpath2 = System.getProperty("user.dir") + "/" + "loan.csv";
File csv1 = new File(fullpath);
File csv2 = new File(fullpath2);
List<String> csv1Headers = CsvParser.getHeadersFromACsv(csv1);
// csv1Headers.forEach(h -> System.out.print(h + " "));
// System.out.println();
List<String> csv2Headers = CsvParser.getHeadersFromACsv(csv2);
// csv2Headers.forEach(h -> System.out.print(h + " "));
// System.out.println();
List<String> allCsvHeaders = new ArrayList<>();
allCsvHeaders.addAll(csv1Headers);
allCsvHeaders.addAll(csv2Headers);
// allCsvHeaders.forEach(h -> System.out.print(h + " "));
// System.out.println();
Set<String> uniqueHeaders = new LinkedHashSet<>(allCsvHeaders);
// uniqueHeaders.forEach(h -> System.out.print(h + " "));
// System.out.println();
List<CsvVo> csv1Records = CsvParser.getRecodrsFromACsv(csv1, csv1Headers, "employee");
List<CsvVo> csv2Records = CsvParser.getRecodrsFromACsv(csv2, csv2Headers, "loan");
List<Employee> allEmployees = new ArrayList<>();
for(int i = 0; i < csv1Records.size(); i++) {
allEmployees.add(csv1Records.get(i).get(CsvParser.key1));
System.out.println(csv1Records.get(i).get(CsvParser.key1));
}
List<Loan> allLoans = new ArrayList<>();
for(int i = 0; i < csv1Records.size(); i++) {
allLoans.add(csv2Records.get(i).get(CsvParser.key2));
}
Multimap<String, Loan> loansByID = allLoans.stream().collect(MultimapCollector.toMultimap(Loan::getLoanId));
List<OutputData[]> result = allEmployees.stream().map(emp -> {
OutputData[] p = new OutputData[1];
p[0] = new OutputData(emp.getNameOfEmployee(), emp.getProprieties(), null, null);
String z = emp.getProprieties().get("empid").toString().replace("\"", "");
emp.setEmployeeId(z);
Collection<Loan> loan = loansByID.get(z);
int size = loan.size();
if(size > 0) {
p = new OutputData[size];
for(int j = 0; j < p.length; j++) {
p[j] = new OutputData(emp.getNameOfEmployee(), emp.getProprieties(), null, null);
}
}
int index = 0;
for(Loan oneloan : loan) {
if(oneloan != null) {
// now set all the OutputData fields based on the properties
// of the Employees instance (emp) and the Loans instance (oneloan)
// (if available)
// String nameOfEmployee, JsonObject proprieties, String nameOfLoan,
// JsonObject proprieties2
p[index].setNameOfEmployee(emp.getNameOfEmployee());
p[index].setProprieties(emp.getProprieties());
p[index].setNameOfLoan(oneloan.getNameOfLoan());
p[index].setProprieties2(oneloan.getProprieties2());
}
index++;
}
return p;
}).collect(Collectors.toList());
List<OutputData> allCsvRecords = new ArrayList<>();
List<OutputData> lresult = result.stream().flatMap(Stream::of).collect(Collectors.toList());
allCsvRecords.addAll(lresult);
String fullpath3 = System.getProperty("user.dir") + "/" + "mergingresults.csv";
CsvParser.writeToCsv(new File(fullpath3), uniqueHeaders, allCsvRecords);
}
}
这会产生所需的输出:
nameOfEmployee,proprieties,nameOfLoan,proprieties2
Kevin,{"empid":1,"age":50,"education":"abc college"},pc,{"loan":4777.00,"balance":280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},home,{"loan":140000.00,"balance":60080.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},kitchen,{"loan":4000.00,"balance":3280.0,"empid":1}
Kevin,{"empid":1,"age":50,"education":"abc college"},car,{"loan":140000.00,"balance":60080.0,"empid":1}
Carole,{"empid":2,"age":25,"education":"koala college"},health,{"loan":1400,"balance":2800.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},trip,{"loan":14000.00,"balance":6080.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},food,{"loan":400.00,"balance":328.0,"empid":2}
Carole,{"empid":2,"age":25,"education":"koala college"},education,{"loan":14000.00,"balance":60080.0,"empid":2}
Sebastian,{"empid":3,"age":47,"education":"Rubbits college"},null,null
Daniel,{"empid":4,"age":30,"education":"Pencil college"},null,null
David,{"empid":5,"age":20,"education":"Kodi college"},null,null
Michael,{"empid":6,"age":19,"education":"red college"},null,null
Alain,{"empid":7,"age":35,"education":"green college"},null,null
Rachel,{"empid":8,"age":55,"education":"white college"},null,null
关于java - 如何在2个不同类型的列表中查找元素匹配并使用java 8流连接它们？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/60588488/