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