SpringBoot调用 Web API 接口

API接口1：添加一条记录

    @PostMapping(path="/addUser")  //用请求参数
    @ResponseBody
    //必须加@RequestBody才能接收到postForObject发来的数据
    public int addUser(@RequestBody User user) {
        try {
            userCrudReposity.save(user);
            return 0;
        }
        catch(Exception e){
            return -1;
        }
    }

调用代码

　　　　 RestTemplate restTemplate = new RestTemplate();
        User user=new User("王","宏伟","email");
        int ret = restTemplate.postForObject("http://localhost:8888/demo/addUser",user,int.class); //int.class是http://localhost:8888/demo/addUser返回的类型
        return ret;

API接口2：添加多条记录

    @PostMapping(path="/addUsers")  //用请求参数
    @ResponseBody
    //必须加@RequestBody才能接收到postForObject发来的数据
    public int addUsers(@RequestBody List<User> list) {
        try {
            userCrudReposity.saveAll(list);
            return 0;
        }
        catch(Exception e){
            return -1;
        }
    }

调用代码：

List<User> list=new ArrayList<User>();
RestTemplate restTemplate = new RestTemplate();
User user1=new User("王","宏伟1","email");
User user2=new User("王","宏伟2","email");
list.add(user1);
list.add(user2);
int ret = restTemplate.postForObject("http://localhost:8888/demo/addUsers",list,int.class);

 API接口3：JSON字符串，添加多条记录

    @PostMapping(path="/addUsers_JSON")  //用请求参数
    @ResponseBody
    //必须加@RequestBody才能接收到postForObject发来的数据
    public int addUsers_JSON(@RequestBody String jsonStr) {
        try {
            jsonStr = URLDecoder.decode(jsonStr,"utf-8");
            List<User> users= JSONArray.parseArray(jsonStr,User.class);
            userCrudReposity.saveAll(users);
            return 0;
        }
        catch(Exception e){
            return -1;
        }
    }

调用代码

        List<User> list=new ArrayList<User>();
        RestTemplate restTemplate = new RestTemplate();
        User user1=new User("王","宏伟a","email");
        User user2=new User("王","宏伟b","email");
        list.add(user1);
        list.add(user2);
        String jsonString=JSON.toJSONString(list);
        String str = URLEncoder.encode(jsonString, "utf-8"); //字符串中中文，必须编码，否则接收错误
        int ret = restTemplate.postForObject("http://localhost:8888/demo/addUsers_JSON",str,int.class);

说明：语句 restTemplate.postForObject("http://localhost:8888/demo/addUsers_JSON",str,int.class);中的中文字符串必须编码，否则接收到后中文错误。

另外一种调用方式

    @GetMapping("/addUsers_JSON2")
    public int addUsers_JSON2()  {
        List<User> list=new ArrayList<User>();
        RestTemplate restTemplate = new RestTemplate();
        User user1=new User("王","宏伟 addUsers_JSON1","email");
        User user2=new User("王","宏伟 addUsers_JSON1","email");
        list.add(user1);
        list.add(user2);
        String jsonString=JSON.toJSONString(list);

        HttpHeaders headers = new HttpHeaders();
        MediaType type = MediaType.parseMediaType("application/json; charset=UTF-8");
        headers.setContentType(type);
        headers.add("Accept", MediaType.APPLICATION_JSON.toString());
        HttpEntity<String> formEntity = new HttpEntity<String>(jsonString, headers);
        int result = restTemplate.postForObject("http://localhost:8888/demo/addUsers_JSON1", formEntity, int.class);  // 这里没有编码，接口不需要解码
        return result;
    }

原因见：https://www.cnblogs.com/zique/p/6171862.html ， 用Postman发送接口能正确接收，应该是发送端格式问题