JAVA-4010: Added new module and moved 3 articles to it

spring-web-modules/spring-resttemplate-3/.gitignore

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+*.class
+
+#folders#
+/target
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

spring-web-modules/spring-resttemplate-3/README.md

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+## Spring RestTemplate
+
+This module contains articles about Spring RestTemplate
+
+### The Course
+The "REST With Spring" Classes: http://bit.ly/restwithspring
+
+### Relevant Articles:
+- [Uploading MultipartFile with Spring RestTemplate](https://www.baeldung.com/spring-rest-template-multipart-upload)
+- [Get and Post Lists of Objects with RestTemplate](https://www.baeldung.com/spring-rest-template-list)
+- [Download a Large File Through a Spring RestTemplate](https://www.baeldung.com/spring-resttemplate-download-large-file)

spring-web-modules/spring-resttemplate-3/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>spring-resttemplate-3</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <name>spring-resttemplate-3</name>
+    <packaging>war</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-boot-2</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- Spring Boot Dependencies -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/resttemplate/lists/EmployeeApplication.java

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+package com.baeldung.resttemplate.lists;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Sample application used to demonstrate working with Lists and RestTemplate.
+ */
+@SpringBootApplication
+public class EmployeeApplication
+{
+    public static void main(String[] args)
+    {
+        SpringApplication.run(EmployeeApplication.class, args);
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/resttemplate/lists/client/EmployeeClient.java

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+package com.baeldung.resttemplate.lists.client;
+
+import com.baeldung.resttemplate.lists.dto.Employee;
+import com.baeldung.resttemplate.lists.dto.EmployeeList;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.client.RestTemplate;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+
+/**
+ * Application that shows how to use Lists with RestTemplate.
+ */
+public class EmployeeClient {
+    public static void main(String[] args) {
+        EmployeeClient employeeClient = new EmployeeClient();
+
+        System.out.println("Calling GET for entity using arrays");
+        employeeClient.getForEntityEmployeesAsArray();
+
+        System.out.println("Calling GET using ParameterizedTypeReference");
+        employeeClient.getAllEmployeesUsingParameterizedTypeReference();
+
+        System.out.println("Calling GET using wrapper class");
+        employeeClient.getAllEmployeesUsingWrapperClass();
+
+        System.out.println("Calling POST using normal lists");
+        employeeClient.createEmployeesUsingLists();
+
+        System.out.println("Calling POST using wrapper class");
+        employeeClient.createEmployeesUsingWrapperClass();
+    }
+
+    public EmployeeClient() {
+
+    }
+
+    public Employee[] getForEntityEmployeesAsArray() {
+
+        RestTemplate restTemplate = new RestTemplate();
+
+        ResponseEntity<Employee[]> response =
+                restTemplate.getForEntity(
+                        "http://localhost:8082/spring-rest/employees/",
+                        Employee[].class);
+
+        Employee[] employees = response.getBody();
+
+        assert employees != null;
+        asList(employees).forEach(System.out::println);
+
+        return employees;
+
+    }
+
+
+    public List<Employee> getAllEmployeesUsingParameterizedTypeReference() {
+        RestTemplate restTemplate = new RestTemplate();
+
+        ResponseEntity<List<Employee>> response =
+                restTemplate.exchange(
+                        "http://localhost:8082/spring-rest/employees/",
+                        HttpMethod.GET,
+                        null,
+                        new ParameterizedTypeReference<List<Employee>>() {
+                        });
+
+        List<Employee> employees = response.getBody();
+
+        assert employees != null;
+        employees.forEach(System.out::println);
+
+        return employees;
+    }
+
+    public List<Employee> getAllEmployeesUsingWrapperClass() {
+        RestTemplate restTemplate = new RestTemplate();
+
+        EmployeeList response =
+                restTemplate.getForObject(
+                        "http://localhost:8082/spring-rest/employees/v2",
+                        EmployeeList.class);
+
+        List<Employee> employees = response.getEmployees();
+
+        employees.forEach(System.out::println);
+
+        return employees;
+    }
+
+    public void createEmployeesUsingLists() {
+        RestTemplate restTemplate = new RestTemplate();
+
+        List<Employee> newEmployees = new ArrayList<>();
+        newEmployees.add(new Employee(3, "Intern"));
+        newEmployees.add(new Employee(4, "CEO"));
+
+        restTemplate.postForObject(
+                "http://localhost:8082/spring-rest/employees/",
+                newEmployees,
+                ResponseEntity.class);
+    }
+
+    public void createEmployeesUsingWrapperClass() {
+        RestTemplate restTemplate = new RestTemplate();
+
+        List<Employee> newEmployees = new ArrayList<>();
+        newEmployees.add(new Employee(3, "Intern"));
+        newEmployees.add(new Employee(4, "CEO"));
+
+        restTemplate.postForObject(
+                "http://localhost:8082/spring-rest/employees/v2/",
+                new EmployeeList(newEmployees),
+                ResponseEntity.class);
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/resttemplate/lists/controller/EmployeeResource.java

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+package com.baeldung.resttemplate.lists.controller;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.resttemplate.lists.dto.Employee;
+import com.baeldung.resttemplate.lists.dto.EmployeeList;
+import com.baeldung.resttemplate.lists.service.EmployeeService;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/employees")
+public class EmployeeResource
+{
+    @Autowired
+    private EmployeeService employeeService;
+
+    @RequestMapping(method = RequestMethod.GET, path = "/")
+    public List<Employee> getEmployees()
+    {
+        return employeeService.getAllEmployees();
+    }
+
+    @RequestMapping(method = RequestMethod.GET, path = "/v2")
+    public EmployeeList getEmployeesUsingWrapperClass()
+    {
+        List<Employee> employees = employeeService.getAllEmployees();
+        return new EmployeeList(employees);
+    }
+
+    @RequestMapping(method = RequestMethod.POST, path = "/")
+    public void addEmployees(@RequestBody List<Employee> employees)
+    {
+        employeeService.addEmployees(employees);
+    }
+
+    @RequestMapping(method = RequestMethod.POST, path = "/v2")
+    public void addEmployeesUsingWrapperClass(@RequestBody EmployeeList employeeWrapper)
+    {
+        employeeService.addEmployees(employeeWrapper.getEmployees());
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/resttemplate/lists/dto/Employee.java

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+package com.baeldung.resttemplate.lists.dto;
+
+public class Employee {
+
+    public long id;
+    public String title;
+
+    public Employee()
+    {
+
+    }
+
+    public Employee(long id, String title)
+    {
+        this.id = id;
+        this.title = title;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    @Override
+    public String toString()
+    {
+        return "Employee #" + id + "["  + title + "]";
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/resttemplate/lists/dto/EmployeeList.java

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+package com.baeldung.resttemplate.lists.dto;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class EmployeeList
+{
+    public List<Employee> employees;
+
+    public EmployeeList()
+    {
+        employees = new ArrayList<>();
+    }
+
+    public EmployeeList(List<Employee> employees)
+    {
+        this.employees = employees;
+    }
+
+    public void setEmployees(List<Employee> employees)
+    {
+        this.employees = employees;
+    }
+
+    public List<Employee> getEmployees()
+    {
+        return employees;
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/resttemplate/lists/service/EmployeeService.java

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+package com.baeldung.resttemplate.lists.service;
+
+import org.springframework.stereotype.Service;
+
+import com.baeldung.resttemplate.lists.dto.Employee;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Service("EmployeeListService")
+public class EmployeeService
+{
+    public List<Employee> getAllEmployees()
+    {
+        List<Employee> employees = new ArrayList<>();
+        employees.add(new Employee(1, "Manager"));
+        employees.add(new Employee(2, "Java Developer"));
+        return employees;
+    }
+
+    public void addEmployees(List<Employee> employees)
+    {
+        employees.forEach(e -> System.out.println("Adding new employee " + e));
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/web/upload/app/UploadApplication.java

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+package com.baeldung.web.upload.app;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
+import org.springframework.context.annotation.ComponentScan;
+
+@EnableAutoConfiguration
+@ComponentScan("com.baeldung.web.upload")
+@SpringBootApplication
+public class UploadApplication extends SpringBootServletInitializer {
+
+    public static void main(final String[] args) {
+        SpringApplication.run(UploadApplication.class, args);
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/web/upload/client/MultipartFileUploadClient.java

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+package com.baeldung.web.upload.client;
+
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestTemplate;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class MultipartFileUploadClient {
+
+    public static void main(String[] args) throws IOException {
+        uploadSingleFile();
+        uploadMultipleFile();
+    }
+
+    private static void uploadSingleFile() throws IOException {
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
+
+        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
+        body.add("file", getTestFile());
+
+
+        HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);
+        String serverUrl = "http://localhost:8082/spring-rest/fileserver/singlefileupload/";
+        RestTemplate restTemplate = new RestTemplate();
+        ResponseEntity<String> response = restTemplate.postForEntity(serverUrl, requestEntity, String.class);
+        System.out.println("Response code: " + response.getStatusCode());
+    }
+
+    private static void uploadMultipleFile() throws IOException {
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
+
+        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
+        body.add("files", getTestFile());
+        body.add("files", getTestFile());
+        body.add("files", getTestFile());
+
+        HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);
+        String serverUrl = "http://localhost:8082/spring-rest/fileserver/multiplefileupload/";
+        RestTemplate restTemplate = new RestTemplate();
+        ResponseEntity<String> response = restTemplate.postForEntity(serverUrl, requestEntity, String.class);
+        System.out.println("Response code: " + response.getStatusCode());
+    }
+
+    public static Resource getTestFile() throws IOException {
+        Path testFile = Files.createTempFile("test-file", ".txt");
+        System.out.println("Creating and Uploading Test File: " + testFile);
+        Files.write(testFile, "Hello World !!, This is a test file.".getBytes());
+        return new FileSystemResource(testFile.toFile());
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/java/com/baeldung/web/upload/controller/FileServerResource.java

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+package com.baeldung.web.upload.controller;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.multipart.MultipartFile;
+
+import java.io.IOException;
+import java.util.List;
+
+@RestController
+@RequestMapping("/fileserver")
+public class FileServerResource {
+
+    @RequestMapping(path = "/singlefileupload/", method = RequestMethod.POST)
+    public ResponseEntity<String> processFile(@RequestParam("file") MultipartFile file) throws IOException {
+
+        byte[] bytes = file.getBytes();
+
+        System.out.println("File Name: " + file.getOriginalFilename());
+        System.out.println("File Content Type: " + file.getContentType());
+        System.out.println("File Content:\n" + new String(bytes));
+
+        return (new ResponseEntity<>("Successful", null, HttpStatus.OK));
+    }
+
+    @RequestMapping(path = "/multiplefileupload/", method = RequestMethod.POST)
+    public ResponseEntity<String> processFile(@RequestParam("files") List<MultipartFile> files) throws IOException {
+
+        for (MultipartFile file : files) {
+            byte[] bytes = file.getBytes();
+
+            System.out.println("File Name: " + file.getOriginalFilename());
+            System.out.println("File Content Type: " + file.getContentType());
+            System.out.println("File Content:\n" + new String(bytes));
+        }
+
+        return (new ResponseEntity<>("Successful", null, HttpStatus.OK));
+    }
+}

spring-web-modules/spring-resttemplate-3/src/main/resources/application.properties

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+server.port=8082
+server.servlet.context-path=/spring-rest

spring-web-modules/spring-resttemplate-3/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+    
+    <logger name="org.springframework.web.filter.CommonsRequestLoggingFilter">
+		<level value="DEBUG" />
+	</logger>
+
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

spring-web-modules/spring-resttemplate-3/src/test/java/com/baeldung/SpringContextTest.java

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+package com.baeldung;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = { com.baeldung.web.upload.app.UploadApplication.class, })
+public class SpringContextTest {
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+}

spring-web-modules/spring-resttemplate-3/src/test/java/com/baeldung/largefile/LargeFileDownloadIntegrationTest.java

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+package com.baeldung.largefile;
+
+import java.io.File;
+import java.io.FileOutputStream;
+
+import org.assertj.core.api.Assertions;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.util.StreamUtils;
+import org.springframework.web.client.RestTemplate;
+
+public class LargeFileDownloadIntegrationTest {
+
+    static String FILE_URL = "http://ovh.net/files/1Mio.dat";
+
+    RestTemplate restTemplate;
+
+    @Before
+    public void setUp() {
+        restTemplate = new RestTemplate();
+    }
+
+    @Test
+    public void givenResumableUrl_whenUrlCalledByHeadOption_thenExpectHeadersAvailable() {
+        HttpHeaders headers = restTemplate.headForHeaders(FILE_URL);
+        Assertions
+          .assertThat(headers.get("Accept-Ranges"))
+          .contains("bytes");
+        Assertions
+          .assertThat(headers.getContentLength())
+          .isGreaterThan(0);
+    }
+
+    @Test
+    public void givenResumableUrl_whenDownloadCompletely_thenExpectCorrectFileSize() {
+        HttpHeaders headers = restTemplate.headForHeaders(FILE_URL);
+        long contentLength = headers.getContentLength();
+        File file = restTemplate.execute(FILE_URL, HttpMethod.GET, null, clientHttpResponse -> {
+            File ret = File.createTempFile("download", "tmp");
+            StreamUtils.copy(clientHttpResponse.getBody(), new FileOutputStream(ret));
+            return ret;
+        });
+
+        Assert.assertNotNull(file);
+        Assertions
+          .assertThat(file.length())
+          .isEqualTo(contentLength);
+    }
+
+    @Test
+    public void givenResumableUrl_whenDownloadRange_thenExpectFileSizeEqualOrLessThanRange() {
+        int range = 10;
+        File file = restTemplate.execute(FILE_URL, HttpMethod.GET, clientHttpRequest -> clientHttpRequest
+          .getHeaders()
+          .set("Range", String.format("bytes=0-%d", range - 1)), clientHttpResponse -> {
+            File ret = File.createTempFile("download", "tmp");
+            StreamUtils.copy(clientHttpResponse.getBody(), new FileOutputStream(ret));
+            return ret;
+        });
+
+        Assert.assertNotNull(file);
+        Assertions
+          .assertThat(file.length())
+          .isLessThanOrEqualTo(range);
+    }
+
+    @Test
+    public void givenResumableUrl_whenPauseDownloadAndResume_thenExpectCorrectFileSize() {
+
+        int range = 10;
+
+        HttpHeaders headers = restTemplate.headForHeaders(FILE_URL);
+        long contentLength = headers.getContentLength();
+
+        File file = restTemplate.execute(FILE_URL, HttpMethod.GET, clientHttpRequest -> clientHttpRequest
+          .getHeaders()
+          .set("Range", String.format("bytes=0-%d", range - 1)), clientHttpResponse -> {
+            File ret = File.createTempFile("download", "tmp");
+            StreamUtils.copy(clientHttpResponse.getBody(), new FileOutputStream(ret));
+            return ret;
+        });
+
+        Assert.assertNotNull(file);
+
+        Assertions
+          .assertThat(file.length())
+          .isLessThanOrEqualTo(range);
+
+        restTemplate.execute(FILE_URL, HttpMethod.GET, clientHttpRequest -> clientHttpRequest
+          .getHeaders()
+          .set("Range", String.format("bytes=%d-%d", file.length(), contentLength)), clientHttpResponse -> {
+            StreamUtils.copy(clientHttpResponse.getBody(), new FileOutputStream(file, true));
+            return file;
+        });
+
+        Assertions
+          .assertThat(file.length())
+          .isEqualTo(contentLength);
+
+    }
+
+}

spring-web-modules/spring-resttemplate-3/src/test/resources/.gitignore

@@ -0,0 +1,13 @@
+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

spring-web-modules/spring-resttemplate-3/src/test/resources/logback-test.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+    
+    <logger name="org.springframework.web.filter.CommonsRequestLoggingFilter">
+		<level value="DEBUG" />
+	</logger>
+
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>