MybatisPlus,无XML分分钟实现CRUD操作

2023-07-18 03:01:04 70

不讲太多理论知识，官网都有，直接上手。

1.测试表

DROPTABLEIFEXISTS`user`;
CREATETABLE`user`(
`id`bigint(20)UNSIGNEDNOTNULL,
`name`varchar(128)CHARACTERSETutf8COLLATEutf8_general_ciDEFAULTNULLCOMMENT'用户名',
`password`varchar(18)CHARACTERSETutf8COLLATEutf8_general_ciDEFAULTNULLCOMMENT'密码',
`age`int(4)DEFAULTNULLCOMMENT'年龄',
`create_time`datetime(0)DEFAULTNULLCOMMENT'创建时间',
`update_time`datetime(0)DEFAULTNULLCOMMENT'更新时间',
PRIMARYKEY(`id`)USINGBTREE
)ENGINE=InnoDBCHARACTERSET=utf8COLLATE=utf8_general_ciROW_FORMAT=Dynamic;

引入依赖



com.baomidou
mybatis-plus-boot-starter
3.0.5



mysql
mysql-connector-java

配置文件，这里我用的是boot项目

spring:
datasource:
username:cjx
password:cjx19950616
url:jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
driver-class-name:com.mysql.cj.jdbc.Driver
mybatis-plus:
mapper-locations:classpath:/mapper/*.xml
#configuration:
#map-underscore-to-camel-case:true

其实简单的crud甚至不需要mybatis-plus的配置，我这里没删除，本文也并没有用到配置文件。

实体类

publicclassUser{
privateLongid;
privateStringname;
privateStringpassword;
privateintage;
privateDatecreateTime;
privateDateupdateTime;

...
getter&&setter
...
toString()
}

分页插件

@Configuration
publicclassMyBtaisPlusConfig{
/**
*分页插件
*@return
*/
@Bean
publicPaginationInterceptorpaginationInterceptor(){
System.out.println("加载分页插件");

returnnewPaginationInterceptor();
}
}

编写一个我们的接口

@Component
publicinterfaceUserDaoextendsBaseMapper{
IntegerdeleteById(Longid);
}

接下来就可以愉快的测试了，在我们的测试类里先注入dao

@Autowired

privateUserDaouserMapper;

新增测试

/**
*新增
*/
@Test
voidsave(){

Useru=newUser();
u.setAge(100);
u.setName("测试数据3");
u.setPassword("cjx1111");
u.setAge(25);
introw=userMapper.insert(u);
System.out.println(row);
}

是不是很简单？只需要这样就可以完成新增了，既然有单个插入，那少不了也有批量插入

批量新增测试

/**
*批量插入
*/
@Test
voidsave(){
Listus=newLinkedList();
for(inti=0;i<50;i++){
Useru=newUser();
u.setName("测试数据"+i);
u.setAge((int)(Math.random()*90+10));
u.setPassword("mima"+i);
us.add(u);
}
userService.saveBatch(us);
}

其中用到了userService，我这里贴一下代码，需要我们接口继承Iservice,实现类继承ServiceImple,这样就可以直接调用mybatis-plus为我们提供的现成方法了。

publicinterfaceIUserServiceextendsIService{

}

实现类

@ServicepublicclassUserServiceImplextendsServiceImplimplementsIUserService{

}

修改

/**
*修改
*/
@Test
voidupdateById(){

Useru=newUser();
//修改name
u.setId(1L);
u.setName("修改下数据--");
u.setPassword("123");
u.setAge(99);
introw=userMapper.updateById(u);
System.out.println(row);
}

/**
*通过id查询
*/
@Test
voidselectById(){
//1.通过id来查询
Useru=userMapper.selectById(1l);
System.out.println(u);

}

mybatis-plus有个特别好用的就是它的条件构造器，可以帮助我们构造常用的sql，具体用法我会贴在文章最后面。

/**
*通过条件构造器查询
*/
@Test
voidselectByWrapper(){

//3.通过条件构造器wrapper
QueryWrapperqw=newQueryWrapper();
qw.like("name","测试");
qw.lt("age",50);//小于
qw.gt("age",15);//大于

Listus=userMapper.selectList(qw);
us.stream().forEach(System.out::println);

}

既然有查询，自然少不了我们最关心的分页

/**
*通过条件构造器和page分页查询
*/
@Test
voidselectByWrapperAndPage(){

//4.通过条件构造器wrapper和Page分页查询
QueryWrapperqw=newQueryWrapper();
qw.like("name","测试");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
qw.orderByDesc("age");

IPageresult=userMapper.selectPage(newPage<>(2,10),qw);

/**
*查询总记录数
*/
@Test
voidselectCount(){

//5.通过条件查询总条数
QueryWrapperqw=newQueryWrapper();
qw.like("name","测试");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
qw.orderByDesc("age");

intcount=userMapper.selectCount(qw);
System.out.println(count);

}

删除

/**
*通过id删除
*/
@Test
voiddelete(){

introw=userMapper.deleteById(27l);
System.out.println(row);
}

/**
*通过id批量删除
*/
@Test
voiddeleteBatch(){

introw=userMapper.deleteBatchIds(Arrays.asList(67l,44l,37l,220l));
System.out.println(row);
}

/**
*通过条件删除
*/
@Test
voiddeleteByWrapper(){

QueryWrapperqw=newQueryWrapper<>();
qw.gt("age",70);
//先来看看有多少数据
introw=userMapper.selectCount(qw);
System.out.println(row);
//删除
intdeleteRow=userMapper.delete(qw);
System.out.println(deleteRow);
}

今天就到这，后续会给大家分享下mybatis-plus提供的sql性能执行分析插件、乐观锁插件以及字段的自动填充。

补充知识：Mybatis-plus自动生成代码后xml文件和mapper映射不到的原因

报了如下错误

找了很久都没找到原因

2020-06-0818:48:12|ERROR|http-nio-8130-exec-3|GlobalExceptionHandler.java:25|service.base.handler.GlobalExceptionHandler|org.apache.ibatis.binding.BindingException:Invalidboundstatement(notfound):service.used.mapper.ClassifyMapper.selectNestedListByParentId
	atorg.apache.ibatis.binding.MapperMethod$SqlCommand.(MapperMethod.java:235)
	atcom.baomidou.mybatisplus.core.override.MybatisMapperMethod.(MybatisMapperMethod.java:50)
	atcom.baomidou.mybatisplus.core.override.MybatisMapperProxy.lambda$cachedMapperMethod$0(MybatisMapperProxy.java:101)
	atjava.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660)
	atcom.baomidou.mybatisplus.core.override.MybatisMapperProxy.cachedMapperMethod(MybatisMapperProxy.java:100)
	atcom.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:95)
	atcom.sun.proxy.$Proxy98.selectNestedListByParentId(UnknownSource)
	atxyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl.nestedList(ClassifyServiceImpl.java:25)
	atxyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl$$FastClassBySpringCGLIB$$85da3417.invoke()
	atorg.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
	atorg.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:685)
	atxyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl$$EnhancerBySpringCGLIB$$3b7bb86f.nestedList()
	atxyz.oneadd.platform.service.used.controller.api.ApiClassifyController.classifyList(ApiClassifyController.java:34)
	atsun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethod)
	atsun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	atsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	atjava.lang.reflect.Method.invoke(Method.java:498)
	atorg.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
	atorg.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
	atorg.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)
	atorg.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888)
	atorg.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
	atorg.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	atorg.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
	atorg.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
	atorg.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
	atorg.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
	atjavax.servlet.http.HttpServlet.service(HttpServlet.java:634)
	atorg.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
	atjavax.servlet.http.HttpServlet.service(HttpServlet.java:741)
	atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	atorg.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	atorg.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
	atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	atorg.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
	atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	atorg.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
	atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	atorg.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
	atorg.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	atorg.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
	atorg.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
	atorg.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	atorg.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	atorg.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
	atorg.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367)
	atorg.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	atorg.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
	atorg.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1591)
	atorg.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	atjava.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	atjava.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	atorg.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	atjava.lang.Thread.run(Thread.java:748)

原因是pom中没有添加bulid依赖

添加依赖后解决问题




src/main/java

**/*.xml

false

以上这篇MybatisPlus,无XML分分钟实现CRUD操作就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持毛票票。

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MybatisPlus,无XML分分钟实现CRUD操作

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