一.创建idea
二.向pom.xml添加依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.7.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<spring-boot.version>2.6.13</spring-boot.version>
<jwt.version>0.7.0</jwt.version>
<fastjson.version>1.2.60</fastjson.version>
<spring-cloud-alibaba.version>2.0.3.RELEASE</spring-cloud-alibaba.version>
<spring-cloud.version>Finchley.SR2</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<!--json-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>${fastjson.version}</version>
<scope>compile</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>${spring-cloud-alibaba.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<classifier>exec</classifier>
</configuration>
</plugin>
</plugins>
</build>三.添加application.yml
server:
port: 100四.创建实体类
package com.jr.entry;
import lombok.Data;
import org.hibernate.validator.constraints.Length;
import org.springframework.stereotype.Component;
import javax.validation.constraints.NotEmpty;
@Component
@Data
public class User {
private String id;
// @NotNull name为空地址
@NotEmpty //name为空值，空双引
private String name;
@Length(min = 6,max = 10)
private String password;
}
五. 创建控制类
package com.jr.controller;
import com.jr.entry.User;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;
@RestController
@RequestMapping("/demo")
public class DemoController {
@PostMapping
public String testJsr303(@Validated @RequestBody User user){
return "ok";
}
}
六.创建启动类
package com;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class SpringBootMain {
public static void main(String[] args) {
SpringApplication.run(SpringBootMain.class,args);
}
} 
1.使用@PostMapping注解时，接口要想成功接受到数据，需要使用x-www-form-urlencoded数据的格式发送数据。
2.使用@PostMapping+@RequestBody注解时，接口要想成功接受到数据需要使用raw数据的格式发送数据。
3.但是使用html静态页面发送post请求时，数据是按照application/x-www-form-urlencoded;charset=UTF-8格式发送的，格式不符合，数据接收不到。
启动启动器
七.使用postman工具
因为前端页面无法模拟，前端页面在这里创建不了，所以我们用postman工具演示。填好上面的地址：http://localhost:100/demo，点击body的raw输入代码后，点击send发送。
八.规范返回值格式
但是发现响应的值，虽然是json格式的。但是这个格式并不是咱们想要的，前台后台都是约定好的数据格式，如果你的数据格式发生了变化，那么就需要特殊处理了，很麻烦。所以我们要对响应的结果做一个处理。每个项目组都不一样，只要会怎么用就行。
8.1添加ResultCode工具类
public enum ResultCode {
SUCCESS(0, "请求成功"),
ERROR(1, "请求失败"),
;
private int code;
private String message;
ResultCode(int code, String message) {
this.code = code;
this.message = message;
}
public int getCode() {
return code;
}
public String getMessage() {
return message;
}
}8.2添加Result类
package com.jr.util;
import lombok.Data;
import java.util.HashMap;
import java.util.Map;
@Data
public class Result {
private Integer code;
private String message;
private Map<String, Object> map = new HashMap<>();
private Result() {
}
public static Result ok() {
Result r = new Result();
r.setCode(ResultCode.SUCCESS.getCode());
r.setMessage(ResultCode.SUCCESS.getMessage());
return r;
}
public static Result error() {
Result r = new Result();
r.setCode(ResultCode.ERROR.getCode());
r.setMessage(ResultCode.ERROR.getMessage());
return r;
}
public Result put(String key, Object value) {
map.put(key, value);
return this;
}
public Object get(String key) {
return map.get(key);
}
}8.3添加ValidationExceptionAdvice工具类
package com.jr.util;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@RestControllerAdvice("com.jr.controller")
public class ValidationExceptionAdvice {
@ExceptionHandler(MethodArgumentNotValidException.class)
public Result handlerMethodArgumentNotValidException(MethodArgumentNotValidException e) {
BindingResult bindingResult = e.getBindingResult();
List<FieldError> fieldErrors = bindingResult.getFieldErrors();
Map<String, Object> map = new HashMap<>();
for (FieldError fieldError : fieldErrors) {
map.put(fieldError.getField(), fieldError.getDefaultMessage());
}
return Result.error().put("data", map);
}
}
重新启动项目
九.自己的idea项目结构
今天就到此位置，希望能帮到大家
