@PathVariable and @RequestParam annotations in Spring Boot Part 2

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Table of Contents:

1. Basic points about @PathVariable and @RequestParam annotations.
2. @PathVariable annotations Example in Spring Boot.
3. @RequestParam example in Spring Boot.

Basic points about @PathVariable and @RequestParam annotations.

@PathVariable annotation-

• This annotation introduced in Spring  3.0, available in org.springframework.web.bind.annotation package.
• Optional elements  ( name, required, value).
• This annotation used as a method parameter.
• It takes placeholder value from URI.
• The example of rest URI when we use @PathVariable – http://localhost:9093/rest/listofbooks/{bookId}

@RequestaParam annotation-

• This annotation introduced in Spring  2.5, available in org.springframework.web.bind.annotation package.
• Optional elements  (name, required, value).
• This annotation used as a method parameter.
• It takes parameter value from URI.
• The example of rest URI when we use @RequestParam –

– http://localhost:9093/rest/listofbooks/{bookId}/book?bookName=book1

@PathVariable annotations Example in Spring Boot.

prerequisites –

• JDK 1.8
• Eclipse
• maven
• postman

Create maven project, Don’t forget to check ‘Create a simple project (skip)’click on next. Fill all details(GroupId – pathvariableexample, ArtifactId – pathvariableexample and name – pathvariableexample) and click on finish. Keep packaging as the jar.

POM.XML

<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> <groupId>pathvariableexample</groupId> <artifactId>pathvariableexample</artifactId> <version>0.0.1-SNAPSHOT</version> <name>pathvariableexample</name> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.2.RELEASE</version> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies> </project>

Book.java

package com.onlintutorials.tech; public class Book { int bookId; String bookName; String bookPrice; public int getBookId() { return bookId; } public void setBookId(int bookId) { this.bookId = bookId; } public String getBookName() { return bookName; } public void setBookName(String bookName) { this.bookName = bookName; } public String getBookPrice() { return bookPrice; } public void setBookPrice(String bookPrice) { this.bookPrice = bookPrice; } }

BookController.java

package com.onlinetutotrials.tech; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import java.util.*; @RestController @RequestMapping(value = "/rest") public class BookController { @RequestMapping(value = "/book/{bookId}",method = RequestMethod.GET) public Book getBookById(@PathVariable int bookId) { List<Book> listBook = createBook(); for(Book book : listBook) { if(book.getBookId() == 1) { return book; } } return null; } public List<Book> createBook() { Book book = new Book(); book.setBookId(1); book.setBookName("book1"); book.setBookPrice("100"); Book book1 = new Book(); book1.setBookId(2); book1.setBookName("book2"); book1.setBookPrice("200"); List<Book> bookList = new ArrayList<Book>(); bookList.add(book); bookList.add(book1); return bookList; } }

SpringMain.java

package com.onlinetutorials.tech; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.ConfigurableApplicationContext; @SpringBootApplication public class SpringMain { public static void main(final String[] args) { final ConfigurableApplicationContext configurableApplicationContext = SpringApplication .run(SpringMain.class, args); } }

Now hit the URL:

http://localhost:8080:/rest/book/1

@RequestParam example in Spring Boot.

Let’s modify the controller class.

BookController.java

package com.onlinetutorials.tech; import org.springframework.web.bind.annotation.PathVariable; 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 java.util.*; @RestController @RequestMapping(value = "/rest") public class BookController { @RequestMapping(value = "/listofbooks/{bookId}/book",method = RequestMethod.GET) public Book getBookById( @PathVariable int bookId, @RequestParam String bookName) { List<Book> listBook = createBook(); for(Book book : listBook) { System.out.println("bookIs is ---"+bookId); System.out.println("bookName is ---"+bookName); if(book.getBookId() == 1 && book.getBookName().equals(bookName)) { return book; } } return null; } public List<Book> createBook() { Book book = new Book(); book.setBookId(1); book.setBookName("book1"); book.setBookPrice("100"); Book book1 = new Book(); book1.setBookId(2); book1.setBookName("book2"); book1.setBookPrice("200"); List<Book> bookList = new ArrayList<Book>(); bookList.add(book); bookList.add(book1); return bookList; } }

Now hit the URL to see the OutPut:

http://localhost:8080:/rest/listpfbooks/1/book?bookName=book1

Source: Java Algos

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