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這篇文章主要介紹MybatisPlus無XML分分鐘實現CRUD的方法是什么，文中介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們一定要看完！
1.測試表
DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `id` bigint(20) UNSIGNED NOT NULL, `name` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用戶名', `password` varchar(18) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '密碼', `age` int(4) DEFAULT NULL COMMENT '年齡', `create_time` datetime(0) DEFAULT NULL COMMENT '創建時間', `update_time` datetime(0) DEFAULT NULL COMMENT '更新時間', PRIMARY KEY (`id`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
引入依賴
<!--mybatis-plus核心包--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.0.5</version> </dependency> <!--mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency>
配置文件，這里我用的是boot項目
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
其實簡單的crud甚至不需要mybatis-plus的配置，我這里沒刪除，本文也并沒有用到配置文件。
實體類
public class User{
private Long id;
private String name;
private String password;
private int age;
private Date createTime;
private Date updateTime;
...
getter && setter
...
toString()
}分頁插件
@Configuration
public class MyBtaisPlusConfig {
/**
* 分頁插件
* @return
*/
@Bean
public PaginationInterceptor paginationInterceptor() {
System.out.println("加載分頁插件");
return new PaginationInterceptor();
}
}編寫一個我們的接口
@Component
public interface UserDao extends BaseMapper<User> {
Integer deleteById(Long id);
}接下來就可以愉快的測試了，在我們的測試類里先注入dao
@Autowired
private UserDao userMapper;
新增測試
/**
* 新增
*/
@Test
void save(){
User u = new User();
u.setAge(100);
u.setName("測試數據3");
u.setPassword("cjx1111");
u.setAge(25);
int row = userMapper.insert(u);
System.out.println(row);
}是不是很簡單？只需要這樣就可以完成新增了，既然有單個插入，那少不了也有批量插入
批量新增測試
/**
* 批量插入
*/
@Test
void save(){
List<User> us = new LinkedList<User>();
for (int i = 0;i < 50;i++){
User u = new User();
u.setName("測試數據"+i);
u.setAge((int)(Math.random()*90+10));
u.setPassword("mima"+i);
us.add(u);
}
userService.saveBatch(us);
}其中用到了userService，我這里貼一下代碼，需要我們接口繼承Iservice,實現類繼承ServiceImple<M,T>,這樣就可以直接調用mybatis-plus為我們提供的現成方法了。
public interface IUserService extends IService<User> {
}
實現類
@Service public class UserServiceImpl extends ServiceImpl<UserDao, User>implements IUserService {
}
修改
/**
* 修改
*/
@Test
void updateById(){
User u = new User();
//修改name
u.setId(1L);
u.setName("修改下數據--");
u.setPassword("123");
u.setAge(99);
int row = userMapper.updateById(u);
System.out.println(row);
}/**
* 通過id查詢
*/
@Test
void selectById(){
//1.通過id來查詢
User u = userMapper.selectById(1l);
System.out.println(u);
}mybatis-plus有個特別好用的就是它的條件構造器，可以幫助我們構造常用的sql，具體用法我會貼在文章最后面。
/**
* 通過條件構造器查詢
*/
@Test
void selectByWrapper(){
//3.通過條件構造器wrapper
QueryWrapper qw = new QueryWrapper();
qw.like("name","測試");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
List<User> us = userMapper.selectList(qw);
us.stream().forEach(System.out::println);
}既然有查詢，自然少不了我們最關心的分頁
/**
* 通過條件構造器和page分頁查詢
*/
@Test
void selectByWrapperAndPage(){
//4.通過條件構造器wrapper和Page分頁查詢
QueryWrapper qw = new QueryWrapper();
qw.like("name","測試");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
qw.orderByDesc("age");
IPage<User> result = userMapper.selectPage(new Page<>(2,10),qw);/**
* 查詢總記錄數
*/
@Test
void selectCount(){
//5.通過條件查詢總條數
QueryWrapper qw = new QueryWrapper();
qw.like("name","測試");
qw.lt("age",50);//小于
qw.gt("age",15);//大于
qw.orderByDesc("age");
int count = userMapper.selectCount(qw);
System.out.println(count);
}刪除
/**
* 通過id刪除
*/
@Test
void delete(){
int row = userMapper.deleteById(27l);
System.out.println(row);
}/**
* 通過id批量刪除
*/
@Test
void deleteBatch(){
int row = userMapper.deleteBatchIds(Arrays.asList(67l,44l,37l,220l));
System.out.println(row);
}/**
* 通過條件刪除
*/
@Test
void deleteByWrapper(){
QueryWrapper<User> qw = new QueryWrapper<>();
qw.gt("age",70);
//先來看看有多少數據
int row = userMapper.selectCount(qw);
System.out.println(row);
//刪除
int deleteRow = userMapper.delete(qw);
System.out.println(deleteRow);
}今天就到這，后續會給大家分享下mybatis-plus提供的sql性能執行分析插件、樂觀鎖插件以及字段的自動填充。
補充知識：Mybatis-plus 自動生成代碼后xml文件和mapper映射不到的原因
報了如下錯誤
找了很久都沒找到原因
2020-06-08 18:48:12 |ERROR |http-nio-8130-exec-3 |GlobalExceptionHandler.java:25 |service.base.handler.GlobalExceptionHandler |org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): service.used.mapper.ClassifyMapper.selectNestedListByParentId at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:235) at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.<init>(MybatisMapperMethod.java:50) at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.lambda$cachedMapperMethod$0(MybatisMapperProxy.java:101) at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.cachedMapperMethod(MybatisMapperProxy.java:100) at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:95) at com.sun.proxy.$Proxy98.selectNestedListByParentId(Unknown Source) at xyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl.nestedList(ClassifyServiceImpl.java:25) at xyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl$$FastClassBySpringCGLIB$$85da3417.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:685) at xyz.oneadd.platform.service.used.service.impl.ClassifyServiceImpl$$EnhancerBySpringCGLIB$$3b7bb86f.nestedList(<generated>) at xyz.oneadd.platform.service.used.controller.api.ApiClassifyController.classifyList(ApiClassifyController.java:34) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1591) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748)
原因是pom中沒有添加bulid依賴
添加依賴后解決問題
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>以上是MybatisPlus無XML分分鐘實現CRUD的方法是什么的所有內容，感謝各位的閱讀！希望分享的內容對大家有幫助，更多相關知識，歡迎關注億速云行業資訊頻道！
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