spring boot集成mybatis-plus查询数据库的例子
1.导入依赖
我这里用的是maven项目，先在pom.xml中加入依赖：
4.0.0
com..ps
SPRING_MVC_JSON
1.0-SNAPSHOT
jar
org.springframework.boot
spring-boot-starter-parent
1.5.17.RELEASE
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-data-jpa
mysql
mysql-connector-java
com.alibaba
druid-spring-boot-starter
1.1.10
org.springframework.boot
spring-boot-devtools
true
commons-lang
commons-lang
2.2
com.baomidou
mybatis-plus-boot-starter
3.0-RC1
2.添加资源文件
在你的resources目录下添加application.properties文件，文件名字固定：
server.port=8081
#mysql
spring.datasource.url=jdbc:mysql://localhost:3306/m1dn
spring.datasource.username=root
spring.datasource.password=ps123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#Druid
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.druid.stat-view-servlet.login-username=druid
spring.datasource.druid.stat-view-servlet.login-password=123456
3.java代码
结构图：
3.1:Main类
@SpringBootApplication
public class Main {
public static void main(String[] args) throws Exception {
SpringApplication.run(Main.class, args);
}
@EnableTransactionManagement
@Configuration
@MapperScan("com.baomidou.cloud.service.*.mapper*")
public class Config {
/**
* 分页插件
*/
@Bean
public PaginationInterceptor paginationInterceptor() {
return new PaginationInterceptor();
}
}
}
3.2:controller(控制层)：
EmpServlet.java:
@RestController
public class EmpServlet{
@Autowired
private EmpService service;
@GetMapping(value = "/emps")
public Result emps(String checkName,String sal ,String page, String limit ){
Result result = null;
try {
result = service.queryEmps(checkName,sal ,page, limit);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return result;
}
@PostMapping(value = "/emp")
public Result addEmp(Emp emp){
Result result = new Result();
try {
service.addEmp(emp);
}catch (Exception e){
result.setCount(1);
result.setMsg("新增失败"+e.getMessage());
}
return result;
}
@PutMapping(value = "/emp/{userId}")
public Result updateEmp(@PathVariable String userId,Emp emp){
Result result = new Result();
try {
service.updateEmp(emp,userId);
}catch (Exception e){
result.setCount(1);
result.setMsg("修改失败"+e.getMessage());
}
return result;
}
@DeleteMapping(value = "/emp/{userId}")
public Result updateEmp(@PathVariable String userId){
Result result = new Result();
try {
service.delete(userId);
}catch (Exception e){
result.setCount(1);
result.setMsg("删除失败"+e.getMessage());
}
return result;
}
}
3.3:entity（实体类）层
Emp.java类：
@TableName("emp")
public class Emp {
@TableId(type= IdType.AUTO)
private String empno;
private String ename;
private String job;
@TableField("sal")
private String mySal;
private String hiredate;
}
Result.java类：
public class Result {
private int code;
private String msg;
private int count;
private List data;
}
注意：这两个类的set，get的方法就不展示给你们看了，实际是要加的；
3.4：mapper层
EmpMapper.java类：
@Mapper
public interface EmpMapper extends BaseMapper {
}
3.5：service层
EmpService.java接口：
public interface EmpService {
public Result queryEmps(String checkName, String sal, String curPage, String pageNum) throws Exception;
public void addEmp(Emp emp);
void updateEmp(Emp emp, String userId);
void delete(String userId);
}
EmpServiceImpl.java实现类：
@Service
public class EmpServiceImpl implements EmpService {
@Autowired
private EmpMapper empMapper;
public Result queryEmps(String checkName, String sal, String curPage, String pageNum) throws Exception {
int curPageIn = Integer.parseInt(curPage);
int pageNumIn = Integer.parseInt(pageNum);
if(StringUtils.isEmpty(checkName)) {
checkName = "";
}
// 条件构造器
QueryWrapper wrapper = new QueryWrapper();
wrapper.like("ename", checkName);
if(StringUtils.isNotEmpty(sal)) {
wrapper.le("sal", Integer.parseInt(sal));
} // 这里是分页传入的参数：页数和数据量 // 条件构造器
IPage selectPage = empMapper.selectPage(new Page(curPageIn,pageNumIn), wrapper);
Result result = new Result();
result.setCode(0);
result.setCount((int)selectPage.getTotal());
result.setData(selectPage.getRecords());
return result;
}
public void addEmp(Emp empValue) {
empMapper.insert(empValue);
}
public void updateEmp(Emp empValue,String userId) {
empValue.setEmpno(userId);
empMapper.updateById(empValue);
}
public void delete(String userId) {
empMapper.deleteById(userId);
}
}
4..html文件
showEmp.html
Title
注意，这里我运用的layui框架
5.数据库表，以及运行效果
然后直接运行Main类的main方法，再去浏览器上看效果：
