idea逆向生成代码（以MySQL数据库为例）

打开idea数据库设置

View–>Tool Windows–>Database，打开数据库配置

页面右侧要出现红框内容，也可通过红框右侧的Database打开

配置数据库

+号–>Data Source–>MySQL，进入到配置页

填写配置信息，并验证

出现绿色对号验证成功

如果页面下方出现下面这样的，点击Download下载驱动即可

配置好点击OK后，页面右侧出现数据库信息

创建groovy文件

编写groovy文件

import com.intellij.database.model.DasTable
import com.intellij.database.model.ObjectKind
import com.intellij.database.util.Case
import com.intellij.database.util.DasUtil
import java.text.SimpleDateFormat

packageName = ""

// 表字段类型与Java的对应关系
typeMapping = [
        (~/(?i)tinyint|smallint|mediumint|int/)  : "Integer",
        (~/(?i)bool|bit/)                        : "Boolean",
        (~/(?i)float|double|decimal|real/)       : "BigDecimal",
        (~/(?i)blob|binary|bfile|clob|raw|image/): "InputStream",
        (~/(?i)/)                                : "String"
]

FILES.chooseDirectoryAndSave("Choose directory", "Choose where to store generated files") {
    
     dir ->
    SELECTION.filter {
    
     it instanceof DasTable && it.getKind() == ObjectKind.TABLE }.each {
    
     generate(it, dir) }
}

def generate(table, dir) {
    
    
    def className = javaClassName(table.getName(), true)
    def fields = calcFields(table)
    packageName = getPackageName(dir)
    packageName = packageName.toString().replaceAll(";", "")

    def entityDir = dir.toString() + "\\entity"
    createDir(entityDir)
    PrintWriter entityPrintWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(new File(entityDir, className + ".java")), "UTF-8"))
    entityPrintWriter.withPrintWriter {
    
     out -> entity(out, className, fields, table) }

    def mapperDir = dir.toString() + "\\dao"
    createDir(mapperDir)
    PrintWriter mapperPrintWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(new File(mapperDir, className + "Mapper.java")), "UTF-8"))
    mapperPrintWriter.withPrintWriter {
    
     out -> mapper(out, className) }

    def serviceDir = dir.toString() + "\\service"
    createDir(serviceDir)
    PrintWriter servicePrintWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(new File(serviceDir, className + "Service.java")), "UTF-8"))
    servicePrintWriter.withPrintWriter {
    
     out -> service(out, className) }

    def implDir = dir.toString() + "\\service\\impl"
    createDir(implDir)
    PrintWriter implPrintWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(new File(implDir, className + "ServiceImpl.java")), "UTF-8"))
    implPrintWriter.withPrintWriter {
    
     out -> impl(out, className) }
}

/**
 * 创建目录
 * @param path 路径
 * @return
 */
static def createDir(path) {
    
    
    File dir = new File(path);
    if (!dir.exists()) {
    
    
        dir.mkdirs();
    }
}

/**
 * 获取package
 * @param dir 选择的目录
 * @return package
 */
static def getPackageName(dir) {
    
    
    return dir.toString().replaceAll("\\\\", ".").replaceAll("/", ".").replaceAll("^.*src(\\.main\\.java\\.)?", "") + ";"
}

/**
 * 实体类生成
 * @param out 实体类输出流
 * @param className 类名
 * @param fields 表字段信息
 * @param table 表
 * @return 实体类输出流
 */
def entity(out, className, fields, table) {
    
    
    out.println "package $packageName" + ".entity;"
    out.println ""
    out.println "import io.swagger.annotations.ApiModel;"
    out.println "import io.swagger.annotations.ApiModelProperty;"
    out.println "import lombok.Data;"
    out.println ""
    out.println "import javax.persistence.Column;"
    out.println "import javax.persistence.Entity;"
    out.println "import javax.persistence.Table;"
    out.println "import javax.persistence.GeneratedValue;"
    out.println "import javax.persistence.Id;"
    out.println "import java.io.Serializable;"
    Set types = new HashSet()

    fields.each() {
    
    
        types.add(it.type)
    }

    if (types.contains("Date")) {
    
    
        out.println "import java.util.Date;"
    }

    if (types.contains("InputStream")) {
    
    
        out.println "import java.io.InputStream;"
    }

    if (types.contains("BigDecimal")) {
    
    
        out.println "import java.math.BigDecimal;"
    }
    out.println ""
    out.println "/**\n" +
            " * @Description  \n" +
            " * @Author: hyy\n" +
            " * @Date " + new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()) + " \n" +
            " */"
    out.println ""
    out.println "@Data"
    out.println "@Entity"
    out.println "@Table ( name =\"" + table.getName() + "\" )"
    out.println "@ApiModel(description = \"" + table.getName() + "\")"
    out.println "public class $className implements Serializable {"
    fields.each() {
    
    
        out.println ""
        // 输出注释
        if (isNotEmpty(it.commoent)) {
    
    
            out.println "\t/**"
            out.println "\t * ${it.commoent.toString()}"
            out.println "\t */"
            out.println "\t@ApiModelProperty(value = \"${it.commoent.toString()}\")"
        }
        if (it.name == "id") {
    
    
            out.println "\t@Id"
            out.println "\t@GeneratedValue(generator=\"JDBC\")"
        } else {
    
    
            if (it.annos != "") out.println "   ${it.annos.replace("[@Id]", "")}"
        }

        // 输出成员变量
        out.println "\tprivate ${it.type} ${it.name};"
    }

    out.println ""
    out.println "}"
}

/**
 * dao生成
 * @param out 输出流
 * @param className 类名
 * @return
 */
def mapper(out, className) {
    
    
    out.println "package $packageName" + ".dao;"
    out.println ""
    out.println "import $packageName" + ".entity.$className;"
    out.println ""
    out.println "/**\n" +
            " * @Description  \n" +
            " * @Author: hyy\n" +
            " * @Date " + new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()) + " \n" +
            " */"
    out.println "public interface $className" + "Mapper {"
    out.println "}"
}

/**
 * service生成
 * @param out 输出流
 * @param className 类名
 * @return
 */
def service(out, className) {
    
    
    out.println "package $packageName" + ".service;"
    out.println ""
    out.println "/**\n" +
            " * @Description  \n" +
            " * @Author: hyy\n" +
            " * @Date " + new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()) + " \n" +
            " */"
    out.println "public interface $className" + "Service {"
    out.println "}"
}

/**
 * serviceImpl生成
 * @param out 输出流
 * @param className 类名
 * @return
 */
def impl(out, className) {
    
    
    out.println "package $packageName" + ".service.impl;"
    out.println ""
    out.println "import $packageName" + ".dao." + "$className" + "Mapper;"
    out.println "import $packageName" + ".service." + "$className" + "Service;"
    out.println "import org.springframework.stereotype.Service;"
    out.println ""
    out.println "import javax.annotation.Resource;"
    out.println ""
    out.println "/**\n" +
            " * @Description  \n" +
            " * @Author: hyy\n" +
            " * @Date " + new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()) + " \n" +
            " */"
    out.println "@Service"
    out.println "public class $className" + "ServiceImpl implements $className" + "Service {"
    out.println ""
    out.println "\t@Resource"
    out.println "\tprivate $className" + "Mapper " + Case.LOWER.apply(className[0]) + className[1..-1] + "Mapper;"
    out.println ""
    out.println "}"
}

/**
 * 获取表字段信息
 * @param table 表名
 * @return 表字段信息
 */
def calcFields(table) {
    
    
    DasUtil.getColumns(table).reduce([]) {
    
     fields, col ->
        def spec = Case.LOWER.apply(col.getDataType().getSpecification())

        def typeStr = typeMapping.find {
    
     p, t -> p.matcher(spec).find() }.value
        def comm = [
                colName : col.getName(),
                name    : javaName(col.getName(), false),
                type    : typeStr,
                commoent: col.getComment(),
                annos   : "\t@Column(name = \"" + col.getName() + "\" )"]
        if ("id".equals(Case.LOWER.apply(col.getName())))
            comm.annos += ["@Id"]
        fields += [comm]
    }
}

// 处理类名（主要是区除前缀，改成驼峰命名）
def javaClassName(str, capitalize) {
    
    
    def s = com.intellij.psi.codeStyle.NameUtil.splitNameIntoWords(str)
            .collect {
    
     Case.LOWER.apply(it).capitalize() }
            .join("")
            .replaceAll(/[^\p{javaJavaIdentifierPart}[_]]/, "_")

    // 去除开头的tb
    s = s[2..-1]
    capitalize || s.length() == 1 ? s : Case.LOWER.apply(s[0]) + s[1..-1]
}

/**
 * 类名按照驼峰规则修改
 * @param str
 * @param capitalize
 * @return
 */
def javaName(str, capitalize) {
    
    
    def s = com.intellij.psi.codeStyle.NameUtil.splitNameIntoWords(str)
            .collect {
    
     Case.LOWER.apply(it).capitalize() }
            .join("")
            .replaceAll(/[^\p{javaJavaIdentifierPart}[_]]/, "_")
    capitalize || s.length() == 1 ? s : Case.LOWER.apply(s[0]) + s[1..-1]
}

def isNotEmpty(content) {
    
    
    return content != null && content.toString().trim().length() > 0
}

生成文件

右键点击表，然后按照下图依次点击，注意最后一个要选择之前创建的groovy文件

出现下面的样子，选择生成文件的目录

点击OK后，文件生成成功，页面如下，红框内为生成的文件
注意：

• 如果有同名文件会直接替换的
• dao、entity、service、impl文件夹不存在的情况下会自动创建