MyBatis-Plus基本用法--5
1、快速开始
1、pom.xml依赖（注意：spring-boot-starter-web必须引入，否则报错）
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<groupId>com.my.testgroupId>
<artifactId>MyTestProartifactId>
<version>0.0.1-SNAPSHOTversion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.3.3.RELEASEversion>
<relativePath/>
parent>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starterartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>com.baomidougroupId>
<artifactId>mybatis-plus-boot-starterartifactId>
<version>3.3.2version>
dependency>
<dependency>
<groupId>com.h2databasegroupId>
<artifactId>h2artifactId>
<scope>runtimescope>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-jdbcartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
dependency>
dependencies>
project>
2、SpringBoot配置文件application.yml
# DataSource Config
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/my_test?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8
username: root
password: 666666
3、启动类、实体及接口
//启动类
@SpringBootApplication
//扫描继承baseMapper的接口
@MapperScan("com.my")
public class TestApp {
public static void main(String[] args) {
SpringApplication.run(TestApp.class, args);
}
}
//测试类
@RestController
@RequestMapping("test")
class TestController{
@Autowired
private TestMapper testMapper;
@PostMapping("/test1")
public void test1() {
List<Test1> testList = testMapper.selectList(null);
for(Test1 tItem : testList) {
System.out.println(tItem.toString());
}
}
}
//mapper接口
interface TestMapper extends BaseMapper<Test1>{
}
//实体类
class Test1{
private String id;
private String name;
private int age;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Test1 [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
2、代码生成器
AutoGenerator 是 MyBatis-Plus 的代码生成器，通过 AutoGenerator 可以快速生成 Entity、Mapper、Mapper XML、Service、Controller 等各个模块的代码，极大的提升了开发效率。
1、引入依赖
<dependency>
<groupId>com.baomidougroupId>
<artifactId>mybatis-plus-generatorartifactId>
<version>3.3.2version>
dependency>
<dependency>
<groupId>org.freemarkergroupId>
<artifactId>freemarkerartifactId>
<version>2.3.30version>
dependency>
2、创建代码生成器类并配置
package com.my;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
import com.baomidou.mybatisplus.core.toolkit.StringPool;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.InjectionConfig;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import com.baomidou.mybatisplus.generator.config.FileOutConfig;
import com.baomidou.mybatisplus.generator.config.GlobalConfig;
import com.baomidou.mybatisplus.generator.config.PackageConfig;
import com.baomidou.mybatisplus.generator.config.StrategyConfig;
import com.baomidou.mybatisplus.generator.config.TemplateConfig;
import com.baomidou.mybatisplus.generator.config.po.TableInfo;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;
public class CodeGenerator {
/**
*
* 读取控制台内容
*
*/
public static String scanner(String tip) {
Scanner scanner = new Scanner(System.in);
StringBuilder help = new StringBuilder();
help.append("请输入" + tip + "：");
System.out.println(help.toString());
if (scanner.hasNext()) {
String ipt = scanner.next();
if (StringUtils.isNotEmpty(ipt)) {
return ipt;
}
}
throw new MybatisPlusException("请输入正确的" + tip + "！");
}
public static void main(String[] args) {
// 代码生成器
AutoGenerator mpg = new AutoGenerator();
// 全局配置
GlobalConfig gc = new GlobalConfig();
String projectPath = System.getProperty("user.dir");
gc.setOutputDir(projectPath + "/src/main/java");
gc.setAuthor("jobob");
gc.setOpen(false);
// gc.setSwagger2(true); 实体属性 Swagger2 注解
mpg.setGlobalConfig(gc);
// 数据源配置
DataSourceConfig dsc = new DataSourceConfig();
dsc.setUrl("jdbc:mysql://localhost:3306/my_test?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8");
// dsc.setSchemaName("public");
dsc.setDriverName("com.mysql.jdbc.Driver");
dsc.setUsername("root");
dsc.setPassword("666666");
mpg.setDataSource(dsc);
// 包配置
PackageConfig pc = new PackageConfig();
pc.setModuleName(scanner("模块名"));
pc.setParent("com.my.test");
mpg.setPackageInfo(pc);
// 自定义配置
InjectionConfig cfg = new InjectionConfig() {
@Override
public void initMap() {
// to do nothing
}
};
// 如果模板引擎是 freemarker
String templatePath = "/templates/mapper.xml.ftl";
// 如果模板引擎是 velocity
// String templatePath = "/templates/mapper.xml.vm";
// 自定义输出配置
List<FileOutConfig> focList = new ArrayList<>();
// 自定义配置会被优先输出
focList.add(new FileOutConfig(templatePath) {
@Override
public String outputFile(TableInfo tableInfo) {
// 自定义输出文件名 ， 如果你 Entity 设置了前后缀、此处注意 xml 的名称会跟着发生变化！！
return projectPath + "/src/main/resources/mapper/" + pc.getModuleName()
+ "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
}
});
/*
cfg.setFileCreate(new IFileCreate() {
@Override
public boolean isCreate(ConfigBuilder configBuilder, FileType fileType, String filePath) {
// 判断自定义文件夹是否需要创建
checkDir("调用默认方法创建的目录，自定义目录用");
if (fileType == FileType.MAPPER) {
// 已经生成 mapper 文件判断存在，不想重新生成返回 false
return !new File(filePath).exists();
}
// 允许生成模板文件
return true;
}
});
*/
cfg.setFileOutConfigList(focList);
mpg.setCfg(cfg);
// 配置模板
TemplateConfig templateConfig = new TemplateConfig();
// 配置自定义输出模板
//指定自定义模板路径，注意不要带上.ftl/.vm, 会根据使用的模板引擎自动识别
// templateConfig.setEntity("templates/entity2.java");
// templateConfig.setService();
// templateConfig.setController();
templateConfig.setXml(null);
mpg.setTemplate(templateConfig);
// 策略配置
StrategyConfig strategy = new StrategyConfig();
strategy.setNaming(NamingStrategy.underline_to_camel);
strategy.setColumnNaming(NamingStrategy.underline_to_camel);
// strategy.setSuperEntityClass("你自己的父类实体,没有就不用设置!");
strategy.setEntityLombokModel(true);
strategy.setRestControllerStyle(true);
// 公共父类
// strategy.setSuperControllerClass("你自己的父类控制器,没有就不用设置!");
// 写于父类中的公共字段
strategy.setSuperEntityColumns("id");
strategy.setInclude(scanner("表名，多个英文逗号分割").split(","));
strategy.setControllerMappingHyphenStyle(true);
strategy.setTablePrefix(pc.getModuleName() + "_");
mpg.setStrategy(strategy);
mpg.setTemplateEngine(new FreemarkerTemplateEngine());
mpg.execute();
}
}
3、测试结果
3、IService接口使用
通过继承ServiceImp来实现IService接口从而获取多种crud方法，若需要自定义sql则可继承BaseMapper进行手动设置
具体示例如下：
//启动类
@SpringBootApplication
//扫描继承baseMapper的接口
@MapperScan("com.my")
public class TestApp {
public static void main(String[] args) {
SpringApplication.run(TestApp.class, args);
}
}
//测试类
@RestController
@RequestMapping("test")
class TestController{
//直接注入service实现，此时不需BaseMapper
@Autowired
private TestService testServiceImp;
@PostMapping("/test1")
public void test1() {
List<Test1> testList = testServiceImp.list();
for(Test1 tItem : testList) {
System.out.println(tItem.toString());
}
}
}
//mapper接口
interface TestMapper extends BaseMapper<Test1>{
}
//service层继承IService
interface TestService extends IService<Test1>{
}
//直接继承ServiceImpl实现多种crud方法,需进行自定sql时可在BaseMapper中进行配置
@Service
class TestServiceImp extends ServiceImpl<TestMapper, Test1> implements TestService{
}
//实体类
class Test1{
private String id;
private String name;
private int age;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Test1 [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
4、QueryWrapper和UpdateWrapper条件构造器
QueryWrapper使用
//测试类
@RestController
@RequestMapping("test")
class TestController{
//Mapper注入
@Autowired
private TestMapper testMapper;
@PostMapping("/test1")
public void test1() {
QueryWrapper<Test1> query = new QueryWrapper<Test1>();
//
query.eq("name", "yy").eq("age", 45);
List<Test1> testList = testMapper.selectList(query);
for(Test1 tItem : testList) {
System.out.println(tItem.toString());
}
}
}
//service层继承IService
interface TestService extends IService<Test1>{
}
//直接继承ServiceImpl实现多种crud方法,需进行自定sql时可在BaseMapper中进行配置
@Service
class TestServiceImp extends ServiceImpl<TestMapper, Test1> implements TestService{
}
UpdateWrapper使用
主函数如下，其余同上
//测试类
@RestController
@RequestMapping("test")
class TestController{
//Mapper注入
@Autowired
private TestMapper testMapper;
@PostMapping("/test1")
public void test1() {
UpdateWrapper<Test1> updateWrapper = new UpdateWrapper<Test1>();
updateWrapper.eq("id","4");
Test1 test = new Test1();
test.setAge(90);
test.setName("dyy");
testMapper.update(test, updateWrapper);
}
}
5、使用分页插件进行分页查询及排序
//启动类
@SpringBootApplication
//扫描继承baseMapper的接口
@MapperScan("com.my")
public class TestApp {
public static void main(String[] args) {
SpringApplication.run(TestApp.class, args);
}
}
//分页插件配置
@Configuration
class MybatisPlusConfig{
@Bean
public PaginationInterceptor paginationInterceptor() {
PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
paginationInterceptor.setCountSqlParser(new JsqlParserCountOptimize(true));
return paginationInterceptor;
}
}
//测试类
@RestController
@RequestMapping("test")
class TestController{
//Mapper注入
@Autowired
private TestMapper testMapper;
@PostMapping("/test1")
public void test1() {
QueryWrapper<Test1> queryWrapper = new QueryWrapper<Test1>();
//根据age排序
queryWrapper.orderByAsc("age");
//参数一是当前页，参数二是每页个数
IPage<Test1> page = new Page<>(1,10);
page = testMapper.selectPage(page, queryWrapper);
List<Test1> tList = page.getRecords();
for(Test1 item:tList) {
System.out.println(item.toString());
}
}
}
//mapper接口
interface TestMapper extends BaseMapper<Test1>{
}
6、MyBatis-Plus自定义sql
具体如下
//测试类
@RestController
@RequestMapping("test")
class TestController{
//Mapper注入
@Autowired
private TestMapper testMapper;
@PostMapping("/test1")
public void test1() {
QueryWrapper<Test1> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("id", "4");
Test1 test = testMapper.selectTest(queryWrapper);
System.out.println(test.toString());
Test1 test2 = testMapper.selectTest2("4");
System.out.println(test2.toString());
}
}
//mapper接口
interface TestMapper extends BaseMapper<Test1>{
/**
* 使用原有的Wrapper配置时需按照以下格式进行配置
* @param testWrapper
* @return
*/
@Select("SELECT * FROM test1 ${ew.customSqlSegment}")
Test1 selectTest(@Param(Constants.WRAPPER) Wrapper<Test1> testWrapper);
@Select("SELECT * FROM test1 where id = #{id}")
Test1 selectTest2(@Param("id") String id);
}
//service层继承IService
interface TestService extends IService<Test1>{
}
7、逻辑删除
逻辑删除就是删除一条数据时，将一个字段的状态改变，从而使得后面查询数据时，不再进行对此数据的查询，相当于数据不再进行暴露，因此称之为逻辑删除
具体使用方式如下
application.yml
mybatis-plus:
global-config:
db-config:
logic-delete-field: flag #全局逻辑删除的实体字段名(since 3.3.0,配置后可以忽略不配置@TableLogic)
logic-delete-value: 1 #逻辑已删除值(默认为 1)
logic-not-delete-value: 0 #逻辑未删除值(默认为 0)
实体类
//实体类
class Test1{
private String id;
private String name;
private int age;
@TableLogic
private Integer deleted;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Integer getDeleted() {
return deleted;
}
public void setDeleted(Integer deleted) {
this.deleted = deleted;
}
@Override
public String toString() {
return "Test1 [id=" + id + ", name=" + name + ", age=" + age + ", deleted=" + deleted + "]";
}
}