SQL to Java Entity#

Quick Start#

Convert a MySQL CREATE TABLE statement to a Java entity class:

1. Parse the CREATE TABLE statement to extract table name, columns, and constraints
2. Map each MySQL column type to corresponding Java type
3. Convert snake_case column names to camelCase field names
4. Generate entity class with @TableName, @TableId, and JPA annotations
5. Generate getter/setter methods

Configuration#

Before generating the entity class, determine the following:

• Package name: Ask the user for the target package (e.g., com.example.entity)
• Base class: Ask if the entity should extend a base class
• Annotation style: Confirm whether to use MyBatis-Plus annotations (default) or JPA annotations

If the user doesn't specify, use sensible defaults based on the project context.

Type Mapping#

For complete MySQL to Java type mappings, see type_mappings.md.

Quick Reference#

MySQLJavaNotesINT``Integer``BIGINT``Long``VARCHAR``String``TEXT``String``DATETIME``LocalDateTimejava.time.LocalDateTimeTIMESTAMP``LocalDateTimejava.time.LocalDateTimeTINYINT(1)``Integer``DECIMAL``BigDecimaljava.math.BigDecimal

Column Name Conversion#

Convert snake_case to camelCase:

text

user_name    → userName
created_at   → createdAt
user_id      → userId
is_active    → isActive

Class name conversion (PascalCase):

text

user_info    → UserInfo
order_detail → OrderDetail

Annotation Generation#

MyBatis-Plus Annotations#

ConstraintAnnotationTable name@TableName("table_name")Primary key@TableId(type = IdType.AUTO)Column name@TableField("column_name") (only if different from field name)Not mapped@TableField(exist = false)

JPA Annotations (if needed)#

ConstraintAnnotationPrimary key@IdAuto increment@GeneratedValue(strategy = GenerationType.IDENTITY)Column name@Column(name = "column_name")Not null@Column(nullable = false)Unique@Column(unique = true)Length@Column(length = 50)

Example#

Input#

sql

CREATE TABLE `user_info` (
    `id` bigint unsigned NOT NULL AUTO_INCREMENT,
    `name` varchar(50) NOT NULL,
    `age` int DEFAULT NULL,
    `email` varchar(100) NOT NULL,
    `salary` decimal(10,2) DEFAULT NULL,
    `description` text,
    `created_at` datetime DEFAULT CURRENT_TIMESTAMP,
    `is_active` tinyint(1) DEFAULT '1',
    PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='User Table';

Output#

java

package com.example.model;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;

import java.math.BigDecimal;
import java.time.LocalDateTime;

@TableName("user_info")
public class UserInfo {

    @TableId(type = IdType.AUTO)
    private Long id;

    private String name;

    private Integer age;

    private String email;

    private BigDecimal salary;

    private String description;

    private LocalDateTime createdAt;

    private Integer isActive;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public BigDecimal getSalary() {
        return salary;
    }

    public void setSalary(BigDecimal salary) {
        this.salary = salary;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public LocalDateTime getCreatedAt() {
        return createdAt;
    }

    public void setCreatedAt(LocalDateTime createdAt) {
        this.createdAt = createdAt;
    }

    public Integer getIsActive() {
        return isActive;
    }

    public void setIsActive(Integer isActive) {
        this.isActive = isActive;
    }
}

Workflow#

1. Extract table info: Get table name, column definitions, constraints, comment
2. Apply type mappings: See type_mappings.md for reference
3. Generate class name: Convert snake_case table name to PascalCase
4. Generate field names: Convert snake_case columns to camelCase
5. Add annotations: Generate @TableName, @TableId, @TableField based on column attributes
6. Generate getters/setters: Create standard getter and setter methods
7. Add imports: Include necessary imports for types and annotations

Package Structure#

Entity classes should be placed in a package specified by the user. Common conventions:

• Generic project: com.{company}.{module}.entity or com.{company}.{module}.model

Class Comment#

Use table comment as class comment:

java

/**
 * User Table
 */
@TableName("user_info")
public class UserInfo extends EntityBean {
}

Base Class#

The entity may extend a framework base class if required:

• Framework: May extend BaseEntity, AbstractEntity, or no base class

Primary Key Strategy#

MySQL Column DefinitionIdTypeAUTO_INCREMENTIdType.AUTOManual assignmentIdType.INPUTUUIDIdType.ASSIGN_UUIDSnowflake algorithmIdType.ASSIGN_ID

Nullable Columns#

For nullable columns (allows NULL), use wrapper types:

• Integer instead of int
• Long instead of long
• Boolean instead of boolean

Important Notes#

1. Always use wrapper types ( Integer, Long, Boolean) for nullable columns
2. Use BigDecimal for DECIMAL/NUMERIC types to maintain precision
3. Use LocalDateTime for DATETIME/TIMESTAMP types
4. Table name in @TableName should match the actual database table name exactly
5. The id field should use IdType.AUTO for auto-increment columns
6. Generate complete getter/setter methods for all fields
7. Follow framework conventions and package structure