一 、Hello案例

1.1 创建maven项目

上一节，我已经学会了手动创建springboot项目。接下来我们用官方的方式来创建

打开 https://start.spring.io/

填好红色部分内容，选择需要的粉红色部分内容，点击绿色箭头下载生成的，解压后导入到工作空间。

pom文件的依赖

<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>com.itcast</groupId>
	<artifactId>springboot-hello-03</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<description>Demo project for Spring Boot</description>
	<!-- 引入springboot父类依赖 -->
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.2.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<!-- spring boot starter -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
		<!-- spring-boot-configuration-processor -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-configuration-processor</artifactId>
			<optional>true</optional>
		</dependency>
		<!-- spring boot starter-test -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- spring boot starter-web -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

1.2 修改入口类的名称，我改成自己喜欢的。生成的太长

package com.itcast;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ItcastApplication {

	public static void main(String[] args) {
		
		SpringApplication.run(ItcastApplication.class, args);

	}

}

1.3创建hello控制器HelloController

package com.itcast.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
 * 访问路径：http://localhost:8080/hello
 * @author jack
 *
 */
@RestController
public class HelloController {
	
	@RequestMapping("/hello")
	public Object hello(){
		return "hello springboot";
	}

}

1.4 启动入口类，访问：http://localhost:8080/hello

二 、返回json案例

2.1 创建一个实体类User

package com.itcast.entity;

import java.util.Date;

public class User {
	private String name;
	private String password;
	private Integer age;
	private Date birthday;
	private String desc;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public String getDesc() {
		return desc;
	}
	public void setDesc(String desc) {
		this.desc = desc;
	}
	@Override
	public String toString() {
		return "User [name=" + name + ", password=" + password + ", age=" + age + ", birthday=" + birthday + ", desc="
				+ desc + "]";
	}

	
}

2.2编写控制层类 UserController

package com.itcast.controller;

import java.util.Date;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.itcast.entity.User;
/**
 * 访问路径：http://localhost:8080/User/getUser
 * @RestController=@Controller+@ResponseBody 返回json
 * @RestController+@ResponseBody返回json
 * @author jack
 *	
 */
@Controller
//@RestController
@RequestMapping("/User")
public class UserController {
	
	@RequestMapping("/getUser")
	@ResponseBody
	public User getUser(){
		User user=new User();
		
		user.setName("花狐貂");
		user.setPassword("123456");
		user.setAge(23);
		user.setBirthday(new Date());
		user.setDesc("帅哥");
		
		return user;
	}
}

2.3启动入口类访问，访问路径：http://localhost:8080/User/getUser

注意：经测试@RestController=@Controller+@ResponseBody 返回json，@RestController+@ResponseBody返回json

三 读取外部资源文件案例

3.1 创建资源配置文件resource.properties，放入classpath路径中

com.itcast.openresource.name=springboot
com.itcast.openresource.website=www.itcast.com
com.itcast.openresource.language=java

3.2创建资源类对象Resource

package com.itcast.entity;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;


@Configuration
@ConfigurationProperties(prefix="com.itcast.openresource")
@PropertySource(value="classpath:resource.properties")
//@PropertySources(value={"classpath:resource.properties"})
public class Resource {
	
	private String name;
	private String  website;
	private String language;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getWebsite() {
		return website;
	}
	public void setWebsite(String website) {
		this.website = website;
	}
	public String getLanguage() {
		return language;
	}
	public void setLanguage(String language) {
		this.language = language;
	}

	
}

3.3 创建资源控制器类ResourceController

package com.itcast.controller;

import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.itcast.entity.Resource;
/**
 *  访问路径：http://localhost:8080/Resource/getResource
 * @author jack
 *
 */
@RestController
@RequestMapping("/Resource")
public class ResourceController {
	@Autowired
	private Resource resource;
	
	@RequestMapping("/getResource")
	public Resource getResource(){
		Resource source=new Resource();
		
		BeanUtils.copyProperties(resource, source);
		return source;
	}
}

3.4 启动入口类访问 访问路径：http://localhost:8080/Resource/getResource

四 ,springboot整合模板引擎freemarker

4.1 新建maven项目，引入freemarker依赖

		<!-- spring boot starter-freemarker freemarker模板依赖  -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-freemarker</artifactId>
		</dependency>

完整pom文件

<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>com.itcast</groupId>
  <artifactId>springboot-freemarker-004</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  
  <!-- 引入springboot父类依赖 -->
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.2.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<!-- spring boot 依赖 -->
		<!-- spring boot starter -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
		<!-- spring-boot-configuration-processor 资源文件-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-configuration-processor</artifactId>
			<optional>true</optional>
		</dependency>
		<!-- spring boot starter-test  -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- spring boot starter-web -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		
		<!-- spring boot starter-freemarker freemarker模板依赖  -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-freemarker</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
  
</project>

4.2 application.properties文件增加freemarker的配置

#########################################################################
#
#freemarker 静态资源配置
#
##########################################################################
#设定ftl文件模板的加载路径，多个以逗号分隔，默认: ["classpath:/templates/"]
spring.freemarker.template-loader-path=classpath:/templates
#是否开启template caching.关闭缓存，及时刷新，上线环境需要改为true
spring.freemarker.cache=false
#设定Template的编码.设置为uft-8
spring.freemarker.charset=utf-8
#是否检查templates路径是否存在.设置为true
spring.freemarker.check-template-location=true
#设定Content-Type.
spring.freemarker.content-type=text/html
#设定所有request的属性在merge到模板的时候，是否要都添加到model中.
spring.freemarker.expose-request-attributes=true
#设定所有HttpSession的属性在merge到模板的时候，是否要都添加到model中.
spring.freemarker.expose-session-attributes=true
#指定RequestContext属性的名.
spring.freemarker.request-context-attribute=request
#设定freemarker模板的前缀.
#spring.freemarker.prefix=

#设定freemarker模板的后缀.
spring.freemarker.suffix=.ftl

#指定使用模板的视图列表.
#spring.freemarker.view-names

#是否允许mvc使用freemarker.
#spring.freemarker.enabled

#指定HttpSession的属性是否可以覆盖controller的model的同名项
#spring.freemarker.allow-session-override

#指定HttpServletRequest的属性是否可以覆盖controller的model的同名项
#spring.freemarker.allow-request-override=false

#设定是否以springMacroRequestContext的形式暴露RequestContext给Spring’s macro library使用
#spring.freemarker.expose-spring-macro-helpers=false

#是否优先从文件系统加载template，以支持热加载，默认为true
#spring.freemarker.prefer-file-system-access

#设定FreeMarker keys.
#spring.freemarker.settings

4.3 新建FreemarkerController控制层

package com.itcast.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;

import com.itcast.entity.Resource;

/**
 * 访问路径：http://localhost:8080/ftl/index
 * 访问路径：http://localhost:8080/ftl/center
 * @author jack
 *
 */

@Controller
@RequestMapping("ftl")
public class FreemarkerController {

	@Autowired
	private Resource resource;
	
	@RequestMapping("/index")
	public String index(ModelMap map){
		map.addAttribute("resource", resource);
		
		return "freemarker/index";
	}
	
	@RequestMapping("/center")
	public String center(){	
		return "freemarker/center/center";
	}
}

4.4 在main/resource目录下新建templates目录，该目录中新增一个index.ftl文件，并增加一个center文件夹其中包含一个center.ft文件。

index.ftl

<!DOCTYPE HTML>
<html>
<head lang="en">
		<meta charser="utf-8">
		<tile>freemarker模板引擎-index page</title>
</head>
<body>
freemarker 模板引擎-index page
<h1>${resource.name}</h1>
<h1>${resource.website}</h1>
<h1>${resource.language}</h1>
</body>
</html>

center.ft

<!DOCTYPE HTML>
<html>
<head lang="en">
		<meta charser="utf-8">
		<tile>freemarker 模板引擎-center page</title>
</head>
<body>
freemarker 模板引擎-center page
<h1>center page</h1>

</body>
</html>

4.5 启动入口类访问

访问路径：http://localhost:8080/ftl/index

<!DOCTYPE HTML>
<html>
<head lang="en">
		<meta charser="utf-8">
		<tile>index page</title>
</head>
<body>
freemarker 模板引擎-index page
<h1>${resource.name}</h1>
<h1>${resource.website}</h1>
<h1>${resource.language}</h1>
</body>
</html>

访问路径：http://localhost:8080/ftl/center

<!DOCTYPE HTML>
<html>
<head lang="en">
		<meta charser="utf-8">
		<tile>center page</title>
</head>
<body>

freemarker 模板引擎-center page
<h1>center page</h1>

</body>
</html>