spring boot和mysql的基本使用（轻松了解接口）

数据库启动后开始 #代表注释

1. 在application.yml文件中绑定你的本地数据库

   #（DBName代表数据库中名称）
   spring:
   datasource:
   driver-class-name: com.mysql.jdbc.Driver
   url: jdbc:mysql://localhost:3306/DBName?characterEncoding=UTF-8&serverTimezone=GMT%2B8
   username: root
   password: password
    #（classpath:sqlmapper/*.xml代表你在springboot中的sql的语句，sqlmapper是放mapper.xml的包名,注意空格是必须要有这是yml文件识别的一直样式）
   mybatis:
      typeAliasesPackage: com.app.demoapp.entiy
      mapperLocations: classpath:mapper/*.xml
   

2.你在springboot中的sql的语句（classpath:sqlmapper/*.xml的XML文件）#代表注释

  <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3- mapper.dtd" >
   #（每个语句中 id=“方法名”中的方法名必须在UserDao中存在这个方法；parameterType代表输入的实体类，resultType代表输出的实体类）
  <mapper namespace="com.app.demoapp.dao.UserDao" >
 <select id="login" parameterType="com.app.demoapp.entiy.UserBean" resultType="com.app.demoapp.entiy.UserBean" >
    select *
    from `user`
    where user_name = #{user_name,jdbcType=VARCHAR}
    and user_pass=#{user_pass,jdbcType=VARCHAR}
 </select>
</mapper>

3.在1和2中都是资源文件中的 UserDao

  @Mapper
  public interface UserDao {
       User login(User user)；
 }

4.实体类User

public class User {
String user_name;
String user_pass;
int user_id;
public String getUser_name() {
    return user_name;
}
public void setUser_name(String user_name) {
    this.user_name = user_name;
}
public String getUser_pass() {
    return user_pass;
}
public void setUser_pass(String user_pass) {
    this.user_pass = user_pass;
}
public int getUser_id() {
    return user_id;
}
public void setUser_id(int user_id) {
    this.user_id = user_id;
}
}

6.在DemoApplication中加@MapperScan("com.meapp.dao")声明dao存在包的位置

 @SpringBootApplication
 @MapperScan("com.app.demoapp.dao")
 public class DemoApplication {
  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
}
}

7.这个是返回值的基本样式

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ApiResult<T> {

/** 代码 */
private int code = 0;

/** 消息 */
private String msg;

/** 数据 */
private T data;

public ApiResult(ApiResult<T> origin) {
    this.code = origin.code;
    this.msg = origin.msg;
    this.data = origin.data;
   
}

public ApiResult() {
}

public ApiResult(T data) {
    this.data = data;
    
}

/**
 * 获取 数据列表
 *
 * @return data 数据列表
 */
public T getData() {
    return this.data;
}

/**
 * 设置 数据列表
 *
 * @param data 数据列表
 */
public void setData(T data) {
    this.data = data;
}

/**
 * 获取 代码
 *
 * @return code 代码
 */
public int getCode() {
    return this.code;
}

/**
 * 设置 代码
 *
 * @param code 代码
 */
public void setCode(int code) {
    this.code = code;
}

/**
 * 获取 消息
 *
 * @return msg 消息
 */
public String getMsg() {
    return this.msg;
}

/**
 * 设置 消息
 *
 * @param msg 消息
 */
public void setMsg(String msg) {
    this.msg = msg;
}
}

8.返回值的样式

@SuppressWarnings("unchecked")
public class ApiResultBuilder {
private ApiResult target;

private ApiResultBuilder() {
    this.target = new ApiResult();
}

public static ApiResultBuilder create() {
    return new ApiResultBuilder();
}

public ApiResultBuilder code(int code) {
    target.setCode(code);
    return this;
}

public ApiResultBuilder msg(String msg) {
    target.setMsg(msg);
    return this;
}

public ApiResultBuilder data(Object data) {
    target.setData(data);
    return this;
}

public ApiResult build() {
    return new ApiResult(target);
}
}

9.最后的胜利接口的写法

@RestController
@EnableAutoConfiguration
@RequestMapping("/user")
public class Login {

@Autowired
UserDao mUserDao;

@PostMapping(value = "/login")
@ResponseStatus(code = HttpStatus.OK)
public ApiResult<User> login(@RequestParam(required = true) String name,
        @RequestParam(required = true) String pass){
    User model = new User();
    model.setUser_name(name);
    model.setUser_pass(pass);
    
    User resultUser = mUserDao.login(model);
    
    return ApiResultBuilder.create().code(1).msg("登录成功").data(resultUser).build();
    
}

@PostMapping(value = "/info")
@ResponseStatus(code = HttpStatus.OK)
public ApiResult<LoginModel> getInfo(@RequestBody LoginModel model1){
    
    
    
    LoginModel model = new LoginModel();
    model.setName("new123456");
    model.setPass("222");
    model.setToken("123456");
    model.setIsNull("");
    return ApiResultBuilder.create().code(1).msg("登录成功").data(model).build();
    
}
}