ResponseEntity使用

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用户4396583

修改于 2024-07-20 00:29:08

190

修改于 2024-07-20 00:29:08

文章被收录于专栏：spring

1.介绍

ResponseEntity继承了HttpEntity类，HttpEntity代表一个http请求或者响应实体，其内部有两个成员变量：header及body，代表http请求或响应的header及body，其中的body是泛化的。

ResponseEntity类，扩展了HttpEntity类，新增了status成员变量，这样，一个ResponseEntity基本可以代表完整的http的请求或响应了。

public class ResponseEntity<T> extends HttpEntity<T> {
	private final Object status;
	public ResponseEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers, HttpStatus status) {
		super(body, headers);
		Assert.notNull(status, "HttpStatus must not be null");
		this.status = status;
	}
    // 省略其他代码
}

2. ResponseEntity常用方法

2.1 只响应：状态码，不响应数据，如insert、update、delete操作时：

//方式一，使用ResponseEntiry的静态方法
return ResponseEntity.status(HttpStatus.BAD_REQUEST); 
//方式二，使用ResponseEntiry的静态方法
return ResponseEntity.status(400); 
//方式三，使用ResponseEntity的构造函数，通过数字状态码解析
return new ResponseEntity<>(HttpStatus.resolve(400)); 
//方式四，使用ResponseEntity的构造函数，通过枚举类型获取
return new ResponseEntity<>(HttpStatus.BAD_REQUEST);

2.2 只响应：数据

//使用ResponseEntiry的静态方法，默认状态码200，pageinfo是分页数据
return ResponseEntity.ok(pageInfo);

2.3 响应：数据和状态码

//使用ResponseEntity的构造函数
return new ResponseEntity<>(pageInfo,HttpStatus.resolve(200));

2.4 响应：状态码和头信息

//创建响应头对象，并添加头信息
HttpHeaders headers = new HttpHeaders();
headers.add("Custom-Header", "foo");
//使用ResponseEntity的构造函数
return new ResponseEntity<>(headers,HttpStatus.resolve(200));

2.5 响应：状态码、数据和头信息

方式一

//创建响应头对象，并添加头信息
HttpHeaders headers = new HttpHeaders();
headers.add("Custom-Header", "foo");
//使用ResponseEntity的构造函数
return new ResponseEntity<>(pageInfo,headers,HttpStatus.resolve(200));

方式二

	//创建响应头对象，并添加头信息
	HttpHeaders headers = new HttpHeaders();
	headers.add("Custom-Header", "foo");
	//使用ResponseEntiry的静态方法，默认状态码200
	return ResponseEntity.ok().header("Custom-Header", "001").body(pageInfo);

3、HttpStatus状态码

HttpStaus是一个枚举类，包含了所有的状态码信息

public enum HttpStatus

package org.example.common.enums;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;

@Getter
@NoArgsConstructor
@AllArgsConstructor
public enum ExceptionEnum {
    PRICE_CANNOT_BE_NULL(400, "价格不能为空"),
    CATEGORY_NOT_FOUND(404, "商品分类没查到"),
    BRAND_NOT_FOUND(404, "品牌不存在"),
    BRAND_SAVE_ERROR(500, "新增品牌失败"),
    ;
    private int code;
    private String msg;

}

常用状态码对应表：其他的自行去HttpStatus枚举中查看

枚举属性	状态码
CONTINUE	100
OK	200
CREATED	201
NO_CONTENT	204
PARTIAL_CONTENT	206
MOVED_PERMANENTLY	301
FOUND	302
NOT_MODIFIED	304
BAD_REQUEST	400
UNAUTHORIZED	401
FORBIDDEN	403
NOT_FOUND	404
INTERNAL_SERVER_ERROR	500
SERVICE_UNAVAILABLE	503

4 其他使用方法

方法一

public class ResponseEntity<T> extends HttpEntity<T> {
    public ResponseEntity(HttpStatus status) {
	    this((Object)null, (MultiValueMap)null, (HttpStatus)status);
	}
	
   public ResponseEntity(@Nullable T body, HttpStatus status) {
        this(body, (MultiValueMap)null, (HttpStatus)status);
    }
	
   public ResponseEntity(MultiValueMap<String, String> headers, HttpStatus status) {
        this((Object)null, headers, (HttpStatus)status);
    }
	
   public ResponseEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers, HttpStatus status) {
        super(body, headers);
        Assert.notNull(status, "HttpStatus must not be null");
        this.status = status;
    }
 
   private ResponseEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers, Object status) {
        super(body, headers);
        Assert.notNull(status, "HttpStatus must not be null");
        this.status = status;
    }
}

这个类提供了五个构造方法，返回的状态码是必传的外，头部信息以及响应体内容都是可选择的。当我们需要使用的时候，直接new一个ResponseEntity对象作为API返回值即可，这就是它的第一种使用方式。

需要注意的是，在有headers作为参数的构造方法中，需要传入一个类型为MultiValueMap<String, String>的参数。MultiValueMap继承自Map这个抽象类，其中拥有一个叫做HttpHeaders的子类，我们可以当它为一个key和value都为String类型的HashMap使用。HttpHeaders里面保存了一些常用的Header的key值，例如"Accept-Charset"。当然也可以自定义一些特殊的key。

HttpHeaders headers = new HttpHeaders();
headers.add("Access-Control-Expose-Headers", "AMP-Access-Control-Allow-Source-Origin");
 
return new ResponseEntity<>(resultBody, headers, HttpStatus.OK);

方法二继续分析源码

    public static ResponseEntity.BodyBuilder status(HttpStatus status) {
        Assert.notNull(status, "HttpStatus must not be null");
        return new ResponseEntity.DefaultBuilder(status);
    }
 
    public static ResponseEntity.BodyBuilder status(int status) {
        return new ResponseEntity.DefaultBuilder(status);
    }
        public static ResponseEntity.BodyBuilder ok() {
        return status(HttpStatus.OK);
    }
    public static ResponseEntity.BodyBuilder created(URI location) {
        ResponseEntity.BodyBuilder builder = status(HttpStatus.CREATED);
        return (ResponseEntity.BodyBuilder)builder.location(location);
    }
 
    public static ResponseEntity.BodyBuilder accepted() {
        return status(HttpStatus.ACCEPTED);
    }
 
    public static ResponseEntity.HeadersBuilder<?> noContent() {
        return status(HttpStatus.NO_CONTENT);
    }
 
    public static ResponseEntity.BodyBuilder badRequest() {
        return status(HttpStatus.BAD_REQUEST);
    }
 
    public static ResponseEntity.HeadersBuilder<?> notFound() {
        return status(HttpStatus.NOT_FOUND);
    }
 
    public static ResponseEntity.BodyBuilder unprocessableEntity() {
        return status(HttpStatus.UNPROCESSABLE_ENTITY);
    }
    //.........

可以用Builder的方式去生成ResponseEntity对象并返回：

Map<String, String> resultBody = new HashMap<>();
resultBody.put("name":"Lucas");
resultBody.put("school":"harvard university");
 return ResponseEntity.status(HttpStatus.OK)
        .body(resultBody);

与其他方式对比

@RestController注解修饰controller层。

@RestController = @Controller + @ResponseBody

@ResponseBody是将controller的方法返回的对象通过适当的转换器转换为指定的格式之后，写入到response对象的body区，通常用来返回JSON数据或者是XML数据。

注意：在使用此注解之后不会再走视图处理器（ModelAndView），而是直接将数据写入到输入流中，他的效果等同于通过response对象输出指定格式的数据。

@ResponseStatus

这个注解主要用在自定义的Exception 上，或者直接用在controller层的API方法上也可，当发生异常/方法执行结束时，会返回相应的Http状态码和msg。

@ResponseStatus(value=HttpStatus.FORBIDDEN,reason="不允许访问")

补充

	//1. 没有返回值: delete  update
	//@GetMapping("/demos")
	public ResponseEntity<Void> demos() {
		 return new ResponseEntity<>(HttpStatus.NO_CONTENT);
	}

	//2 .查询有返回值 查询
	//@GetMapping("/demoss")
	public ResponseEntity<Admin> demoss() {
		return new ResponseEntity<>(new Admin(), HttpStatus.OK);
	}

	//3 . 创建  nodejs  vue
	//@PutMapping("/create")
	public ResponseEntity<Void> create() {
		//return new ResponseEntity<Void>(HttpStatus.CREATED);
		MultiValueMap<String, String> headers = new HttpHeaders();
		headers.set("token", "xiaoli");
		return new ResponseEntity<>(headers, HttpStatus.CREATED);
	}

Get请求时

return ResponseEntity.ok();

@GetMapping({"findAll"})
public ResponseEntity<PageResult<User>> findAll(
    @RequestParam(name = "admin", required = false) String admin, 
    @RequestParam(name = "page", defaultValue = "1") Integer page, 
    @RequestParam(name = "rows", defaultValue = "10") Integer rows
    ) {
        PageResult<User> userPageResult = this.userService.findAll(admin, page, rows);
        return ResponseEntity.ok(userPageResult);
}

Post请求新增一条记录时,有返回值

return ResponseEntity.status(HttpStatus.CREATE).body();

@PostMapping("save")
 public ResponseEntity save(@RequestBody User user) throws Exception {
    return ResponseEntity.status(HttpStatus.CREATED).body(this.userService.save(user));
}

Post请求新增一条记录时,无返回值

return new ResponseEntity(HttpStatus.CREATED);

Delete删除请求,无返回

return new ResponseEntity(HttpStatus.NO_CONTENT);

@DeleteMapping({"delete"})
public ResponseEntity delete(@RequestParam(name = "ids") Integer[] ids) {
    return ResponseEntity.ok(this.userService.delete(ids));
}

Put更新请求，无返回值

ResponseEntity.noContent().build();

@PutMapping({"update"})
public ResponseEntity update(@RequestBody User user) throws Exception {
    return ResponseEntity.ok(this.userService.update(user));
}

1、查询

@GetMapping("queryall")
public ResponseEntity<List<Announceconsultsituation>> queryAll(){
    try {
        List<Announceconsultsituation> announceconsultsituations = announceconsultsituationService.queryList(new Announceconsultsituation());
        if(CollUtil.isEmpty(announceconsultsituations)){
            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(null);
        }
        return ResponseEntity.ok(announceconsultsituations);
    }catch (Exception e){
        e.printStackTrace();
    }
    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
}

@GetMapping("queryone")
public ResponseEntity<List<Announceconsultsituation>> queryone(){
    try {
        Announceconsultsituation announceconsultsituation = announceconsultsituationService.queryOne(id);
        if(announceconsultsituation==null){
            return ResponseEntity.status(HttpStatus.NOT_FOUND).body(null);
        }
        return ResponseEntity.ok(announceconsultsituation);
    }catch (Exception e){
        e.printStackTrace();
    }
    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
}

2、添加

@PostMapping("add")
public ResponseEntity<Void> add(Announceconsultsituation announceconsultsituation){
    try {
        int count = announceconsultsituationService.add(announceconsultsituation);
        // 添加数据成功，返回201
        if(count == 1){
            return ResponseEntity.status(HttpStatus.CREATED).build();
        }
    }catch (Exception e){
        e.printStackTrace();
    }
    // 执行失败或者发生异常，返回500
    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
}

3、修改

@PutMapping("update")
public ResponseEntity<Void> update(Announceconsultsituation announceconsultsituation){
    try {
        int count = announceconsultsituationService.update(announceconsultsituation);
        // 正常更新数据，返回204
        if(count == 1){
            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
        }
    }catch (Exception e){
        e.printStackTrace();
    }
    // 执行失败或者发生异常，返回500
    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
}

4、删除

@DeleteMapping("del/{id}")
public ResponseEntity<Void> delete(@PathVariable("id") Integer id){
    try {
        //参数没有或者格式错误，返回400
        if(id == null){
            return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
        }
        int count = announceconsultsituationService.delete(id);
        // 正常删除，返回204
        if(count == 1){
            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
        }
    }catch (Exception e){
        e.printStackTrace();
    }
    // 执行失败或者发生异常，返回500
    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
}

自定义ResponeBean进行CRUD

public class RespBean {
    private Integer status;
    private String msg;
    private Object obj;

    public static RespBean build() {
        return new RespBean();
    }

    public static RespBean ok(String msg) {
        return new RespBean(200, msg, null);
    }

    public static RespBean ok(String msg, Object obj) {
        return new RespBean(200, msg, obj);
    }

    public static RespBean error(String msg) {
        return new RespBean(500, msg, null);
    }

    public static RespBean error(String msg, Object obj) {
        return new RespBean(500, msg, obj);
    }

    private RespBean() {
    }

    private RespBean(Integer status, String msg, Object obj) {
        this.status = status;
        this.msg = msg;
        this.obj = obj;
    }

    public Integer getStatus() {
        return status;
    }

    public RespBean setStatus(Integer status) {
        this.status = status;
        return this;
    }

    public String getMsg() {
        return msg;
    }

    public RespBean setMsg(String msg) {
        this.msg = msg;
        return this;
    }

    public Object getObj() {
        return obj;
    }

    public RespBean setObj(Object obj) {
        this.obj = obj;
        return this;
    }
}

1、查询

@GetMapping("/")
public List<JobLevel> getAllJobLevels() {
	return jobLevelService.getAllJobLevels();
}

2、增加

@PostMapping("/")
public RespBean addJobLevel(@RequestBody JobLevel jobLevel) {
	if (jobLevelService.addJobLevel(jobLevel) == 1) {
    	return RespBean.ok("添加成功!");
    }
    return RespBean.error("添加失败!");
}

3、更新

@PutMapping("/")
public RespBean updateJobLevelById(@RequestBody JobLevel jobLevel) {
	if (jobLevelService.updateJobLevelById(jobLevel) == 1) {
    	return RespBean.ok("更新成功!");
    }
    return RespBean.error("更新失败!");
}

4、删除

@DeleteMapping("/{id}")
public RespBean deleteJobLevelById(@PathVariable Integer id) {
	if (jobLevelService.deleteJobLevelById(id) == 1) {
    	return RespBean.ok("删除成功!");
    }
    return RespBean.error("删除失败!");
}

原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。

如有侵权，请联系 cloudcommunity@tencent.com 删除。

spring boot

原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。

如有侵权，请联系 cloudcommunity@tencent.com 删除。

spring boot

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