informasi kontak saya
Surat[email protected]
2024-07-12
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Dalam pengembangan Java, MyBatis, sebagai kerangka lapisan persistensi yang sangat baik, banyak digunakan di berbagai proyek dengan konfigurasi sederhana dan fungsi yang kuat. Artikel ini akan memperkenalkan secara rinci empat metode penulisan SQL di lapisan mapper di MyBatis, dan menjelaskan secara rinci melalui kode implementasi tertentu, dengan mengambil tabel pengguna sebagai contoh.
MyBatis adalah kerangka kerja semi-ORM yang memetakan SQL ke dalam file XML atau anotasi, menyederhanakan operasi database. Ini mendukung SQL khusus, prosedur tersimpan, dan pemetaan tingkat lanjut.
Berikut ini contoh struktur proyek sederhana berdasarkan Spring Boot dan MyBatis:
springboot-template-mybatis
│ pom.xml
│
├─src
│ └─main
│ ├─java
│ │ └─com
│ │ └─zcs
│ │ │ Application.java
│ │ │
│ │ ├─common
│ │ │ Result.java
│ │ │
│ │ ├─controller
│ │ │ UserControllerByAnnotation.java
│ │ │ UserControllerByMap.java
│ │ │ UserControllerByProvider.java
│ │ │ UserControllerByXml.java
│ │ │
│ │ ├─entity
│ │ │ UserEntity.java
│ │ │
│ │ ├─mapper
│ │ │ │ UserMapperByAnnotation.java
│ │ │ │ UserMapperByMap.java
│ │ │ │ UserMapperByProvider.java
│ │ │ │ UserMapperByXml.java
│ │ │ │
│ │ │ └─provider
│ │ │ UserProvider.java
│ │ │
│ │ └─service
│ │ UserService.java
│ │ UserServiceByMap.java
│ │
│ └─resources
│ │ application.yml
│ │ log4j.properties
│ │
│ └─com
│ └─zcs
│ └─mapper
│ UserMapperByXml.xml
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
import lombok.Data;
@Data
public class UserEntity {
private Integer id;
private String name;
private Integer age;
}
import com.zcs.entity.UserEntity;
import org.apache.ibatis.annotations.Mapper;
import java.util.List;
@Mapper
public interface UserMapperByXml {
List<UserEntity> selectAllUsersByXml();
boolean insertUserByXml(UserEntity user);
boolean updateUserByXml(UserEntity user);
boolean deleteUserByXml(Integer id);
}
<?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">
<mapper namespace="com.zcs.mapper.UserMapperByXml">
<!-- 查询所有用户 -->
<select id="selectAllUsersByXml">
SELECT *
FROM user
</select>
<!-- 插入用户 -->
<insert id="insertUserByXml">
INSERT INTO user (id, name, age)
VALUES (#{id}, #{name}, #{age})
</insert>
<!-- 更新用户 -->
<update id="updateUserByXml">
UPDATE user
SET name = #{name},
age = #{age}
WHERE id = #{id}
</update>
<!-- 删除用户 -->
<delete id="deleteUserByXml">
DELETE
FROM user
WHERE id = #{id}
</delete>
</mapper>
import com.zcs.common.Result;
import com.zcs.entity.UserEntity;
import com.zcs.mapper.UserMapperByXml;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import java.util.List;
@Slf4j
@RestController
@RequestMapping("/usersByXml")
public class UserControllerByXml {
@Resource
private UserMapperByXml userMapperByXml;
@GetMapping
public Result<List<UserEntity>> selectAllUsersByAnnotation() {
List<UserEntity> userEntities = userMapperByXml.selectAllUsersByXml();
return Result.success("successfully", userEntities);
}
@PostMapping
public Result<String> insertUserByAnnotation(@RequestBody UserEntity user) {
boolean b = userMapperByXml.insertUserByXml(user);
if (b) {
return Result.success("successfully", "数据插入成功");
}
return Result.error(500, "数据插入失败");
}
@PutMapping
public Result<String> updateUserByAnnotation(@RequestBody UserEntity user) {
boolean b = userMapperByXml.updateUserByXml(user);
if (b) {
return Result.success("successfully", "数据更新成功");
}
return Result.error(500, "数据更新失败");
}
@DeleteMapping
public Result<String> deleteUserByAnnotation(@RequestParam Integer id) {
boolean b = userMapperByXml.deleteUserByXml(id);
if (b) {
return Result.success("successfully", "数据删除成功");
}
return Result.error(500, "数据删除失败");
}
}
import com.zcs.entity.UserEntity;
import org.apache.ibatis.annotations.*;
import java.util.List;
@Mapper
public interface UserMapperByAnnotation {
@Select("SELECT * FROM user")
List<UserEntity> getAllUser();
@Insert("INSERT INTO user (id, name, age) VALUES (#{id}, #{name}, #{age})")
@Options(useGeneratedKeys = true, keyProperty = "id")
boolean insertUser(UserEntity user);
@Update("UPDATE user SET name = #{name}, age = #{age} WHERE id = #{id}")
boolean updateUser(UserEntity user);
@Delete("DELETE FROM user WHERE id = #{id}")
boolean deleteUserById(Integer id);
}
import com.zcs.entity.UserEntity;
import com.zcs.mapper.UserMapperByAnnotation;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;
@Service
public class UserServiceByAnnotation {
@Resource
private UserMapperByAnnotation userMapperByAnnotation;
public List<UserEntity> getAllUser() {
return userMapperByAnnotation.getAllUser();
}
public boolean insertUser(UserEntity user) {
return userMapperByAnnotation.insertUser(user);
}
public boolean updateUser(UserEntity user) {
return userMapperByAnnotation.updateUser(user);
}
public boolean deleteUserById(Integer id) {
return userMapperByAnnotation.deleteUserById(id);
}
}
import com.zcs.common.Result;
import com.zcs.entity.UserEntity;
import com.zcs.service.UserServiceByAnnotation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import java.util.List;
@Slf4j
@RestController
@RequestMapping("/usersByAnnotation")
public class UserControllerByAnnotation {
@Resource
private UserServiceByAnnotation userServiceByAnnotation;
@GetMapping
public Result<List<UserEntity>> getAllUser() {
List<UserEntity> allUserM = userServiceByAnnotation.getAllUser();
return Result.success("success", allUserM);
}
@PostMapping
public Result<String> insertUser(@RequestBody UserEntity user) {
boolean b = userServiceByAnnotation.insertUser(user);
if (b) {
return Result.success("success", "数据插入成功");
}
return Result.error(500, "数据插入失败");
}
@PutMapping
public Result<String> updateUser(@RequestBody UserEntity user) {
boolean b = userServiceByAnnotation.updateUser(user);
if (b) {
return Result.success("success", "数据更新成功");
}
return Result.error(500, "数据更新失败");
}
@DeleteMapping
public Result<String> deleteUserById(@RequestParam Integer id) {
boolean b = userServiceByAnnotation.deleteUserById(id);
if (b) {
return Result.success("success", "数据删除成功");
}
return Result.error(500, "数据删除失败");
}
}
import com.zcs.entity.UserEntity;
import org.apache.ibatis.jdbc.SQL;
public class UserProvider {
public String selectAllUser() {
SQL sql = new SQL();
sql.SELECT("*");
sql.FROM("user");
return sql.toString();
}
public String insertUser(UserEntity userEntity) {
SQL sql = new SQL();
sql.INSERT_INTO("user");
if (userEntity.getId() != null) {
sql.VALUES("id", "#{id}");
}
if (userEntity.getName() != null) {
sql.VALUES("name", "#{name}");
}
if (userEntity.getAge() != null) {
sql.VALUES("age", "#{age}");
}
return sql.toString();
}
public String updateUser(UserEntity userEntity) {
SQL sql = new SQL();
sql.UPDATE("user");
if (userEntity.getName() != null) {
sql.SET("name = #{name}");
}
if (userEntity.getAge() != null) {
sql.SET("age = #{age}");
}
sql.WHERE("id = #{id}");
return sql.toString();
}
public String deleteUserById(Integer id) {
SQL sql = new SQL();
sql.DELETE_FROM("user");
sql.WHERE("id = #{id}");
return sql.toString();
}
}
import com.zcs.entity.UserEntity;
import com.zcs.mapper.provider.UserProvider;
import org.apache.ibatis.annotations.*;
import java.util.List;
@Mapper
public interface UserMapperByProvider {
@SelectProvider(type = UserProvider.class, method = "selectAllUser")
List<UserEntity> selectAllUser();
@InsertProvider(type = UserProvider.class, method = "insertUser")
@Options(useGeneratedKeys = true, keyProperty = "id")
boolean insertUser(UserEntity userEntity);
@UpdateProvider(type = UserProvider.class, method = "updateUser")
boolean updateUser(UserEntity userEntity);
@DeleteProvider(type = UserProvider.class, method = "deleteUserById")
boolean deleteUserById(Integer id);
}
import com.zcs.common.Result;
import com.zcs.entity.UserEntity;
import com.zcs.mapper.UserMapperByProvider;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import java.util.List;
@Slf4j
@RestController
@RequestMapping("/usersByProvider")
public class UserControllerByProvider {
@Resource
private UserMapperByProvider userMapper;
@GetMapping
public Result<List<UserEntity>> selectAllUsersByAnnotation() {
List<UserEntity> userEntities = userMapper.selectAllUser();
return Result.success("successfully", userEntities);
}
@PostMapping
public Result<String> insertUserByAnnotation(@RequestBody UserEntity user) {
boolean b = userMapper.insertUser(user);
if (b) {
return Result.success("success", "数据插入成功");
}
return Result.error(500, "数据插入失败");
}
@PutMapping
public Result<String> updateUserByAnnotation(@RequestBody UserEntity user) {
boolean b = userMapper.updateUser(user);
if (b) {
return Result.success("success", "数据更新成功");
}
return Result.error(500, "数据更新失败");
}
@DeleteMapping
public Result<String> deleteUserByAnnotation(@RequestParam Integer id) {
boolean b = userMapper.deleteUserById(id);
if (b) {
return Result.success("success", "数据删除成功");
}
return Result.error(500, "数据删除失败");
}
}
import org.apache.ibatis.annotations.*;
import java.util.List;
import java.util.Map;
@Mapper
public interface UserMapperByMap {
@Select("${sql}")
List<Map<String, Object>> getAllUser(Map<String, Object> map);
@Insert("${sql}")
@Options(useGeneratedKeys = true, keyProperty = "id")
boolean insertUser(Map<String, Object> map);
@Update("${sql}")
boolean updateUser(Map<String, Object> map);
@Delete("${sql}")
boolean deleteUserById(Map<String, Object> map);
}
import com.zcs.mapper.UserMapperByMap;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
@Service
public class UserServiceByMap {
@Resource
private UserMapperByMap userMapperByMap;
public List<Map<String, Object>> getAllUser(Map<String, Object> map) {
String sql = "SELECT * FROM user";
map.put("sql", sql);
return userMapperByMap.getAllUser(map);
}
public boolean insertUser(Map<String, Object> map) {
String sql = "INSERT INTO user (id, name, age) VALUES (#{id}, #{name}, #{age})";
map.put("sql", sql);
return userMapperByMap.insertUser(map);
}
public boolean updateUser(Map<String, Object> map) {
String sql = "UPDATE user SET name = #{name}, age = #{age} WHERE id = #{id}";
map.put("sql", sql);
return userMapperByMap.updateUser(map);
}
public boolean deleteUserById(Map<String, Object> map) {
String sql = "DELETE FROM user WHERE id = #{id}";
map.put("sql", sql);
return userMapperByMap.deleteUserById(map);
}
}
import com.zcs.common.Result;
import com.zcs.service.UserServiceByMap;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@Slf4j
@RestController
@RequestMapping("/usersByMap")
public class UserControllerByMap {
@Resource
private UserServiceByMap userServiceByMap;
@GetMapping
public Result<List<Map<String, Object>>> getAllUser() {
HashMap<String, Object> map = new HashMap<>();
List<Map<String, Object>> allUser = userServiceByMap.getAllUser(map);
return Result.success("success", allUser);
}
@PostMapping
public Result<String> insertUser(@RequestBody Map<String, Object> map) {
boolean b = userServiceByMap.insertUser(map);
if (b) {
return Result.success("success", "数据插入成功");
}
return Result.error(500, "数据插入失败");
}
@PutMapping
public Result<String> updateUserM(@RequestBody Map<String, Object> map) {
boolean b = userServiceByMap.updateUser(map);
if (b) {
return Result.success("success", "数据更新成功");
}
return Result.error(500, "数据更新失败");
}
@DeleteMapping
public Result<String> deleteUserByIdM(@RequestParam Map<String, Object> map) {
boolean b = userServiceByMap.deleteUserById(map);
if (b) {
return Result.success("success", "数据删除成功");
}
return Result.error(500, "数据删除失败");
}
}
Artikel ini memperkenalkan secara rinci empat metode penulisan SQL di lapisan mapper MyBatis, termasuk menggunakan file XML, anotasi, menyediakan kelas, dan meneruskan SQL sebagai parameter. Melalui kode implementasi yang spesifik, pembaca dapat lebih memahami kelebihan dan kekurangan masing-masing metode dan memilih metode yang sesuai dengan kebutuhan sebenarnya.