IDEA 逆向工程

今天要写一个导入功能，需要把数据库的一个表映射成一个pojo，但是这表字段不是一般的多啊。。。想了想能不能自动生成？？？在IDEA中点了半天发现还是可以的

下面介绍一下步骤：

第一步：找到这个图标，建立一个数据库连接

建立完成之后如下图:

第二部修改生成pojo的脚本，切换到这个视图

主要是修改包名：

把上图中的packageName修改成生成pojo存放位置的包即可

第三步：选中要生成实体类的表（可以多选），右键按下图即可生成

如果项目中使用了Lombok插件的话，可以扩展一下自带的Generate POJOs.groovy就可很快的生成我们想要形式的pojo

下面是我的这个工程结构：

这是一个典型的maven工程结构，针对maven工程，扩展的两个groovy脚本，两个脚本均可以根据选择的文件夹自动生成正确的包名

Generate POJOs For Hibernate Lombok.groovy 这个脚本用来生成Hibernate的实体类，要注意两点：1、主键名必须是“id”，2、如果表中有版本字段，那么版本字段名必须是"version"，3、这脚本生成的实体类，主键生成策略没有采用自增模式，如果你的表中主键设置了自增的话，

需要稍微改动一下才可以用

 import com.intellij.database.model.DasTable
 import com.intellij.database.model.ObjectKind
 import com.intellij.database.util.Case
 import com.intellij.database.util.DasUtil

 /*
  * Available context bindings:
  *   SELECTION   Iterable<DasObject>
  *   PROJECT     project
  *   FILES       files helper
  */
 typeMapping = [
         (~/(?i)int/)                      : "long",
         (~/(?i)float|double|decimal|real/): "double",
         (~/(?i)datetime|timestamp/)       : "java.sql.Timestamp",
         (~/(?i)date/)                     : "java.sql.Date",
         (~/(?i)time/)                     : "java.sql.Time",
         (~/(?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 = javaName(table.getName(), true)
     def fields = calcFields(table)
     def tableName = table.getName()
     def path = dir.getPath()
     def packageName = path.substring(path.lastIndexOf("java") + 5, path.length()).replaceAll("\\\\", ".")
     new File(dir, className + ".java").withPrintWriter { out -> generate(out, tableName, className, fields, packageName) }
 }

 def generate(out, tableName, className, fields, packageName) {
     out.println "package $packageName;"
     out.println ""
     out.println "import lombok.Data;"
     out.println "import org.hibernate.annotations.DynamicInsert;"
     out.println "import org.hibernate.annotations.DynamicUpdate;"
     out.println "import org.hibernate.annotations.GenericGenerator;"
     out.println ""
     out.println "import javax.persistence.*;"
     out.println "import java.io.Serializable;"
     out.println ""
     out.println "@Data"
     out.println "@Entity"
     out.println "@Table(name = \"${tableName}\")"
     out.println "@DynamicUpdate(true)"
     out.println "@DynamicInsert(true)"
     out.println "public class $className  implements Serializable{"
     out.println ""
     out.println "\tprivate static final long serialVersionUID = 33163593958226L;"
     out.println ""
     fields.each() {
         if (it.annos != "") out.println "\t${it.annos}"
         out.println "\tprivate ${it.type} ${it.name};"
         out.println ""
     }
     out.println "}"
 }

 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
         if (col.getName().toLowerCase() == "id") {
             fields += [[name : javaName(col.getName(), false),
                         type : typeStr,
                         annos: "@Id\n" +
                                 "\t@GeneratedValue(generator = \"" + table.getName() + "IDGenerator\" , strategy = GenerationType.AUTO)\n" +
                                 "\t@GenericGenerator(name = \"" + table.getName() + "IDGenerator\" , strategy = \"uuid\")\n" +
                                 "\t@Column(name =\"" + col.getName() + "\")"]]
         }  else if(col.getName().toLowerCase() == "version"){
             fields += [[name : javaName(col.getName(), false),
                         type : typeStr,
                         annos: "@Version\n" +
                                 "\t@Column(name =\"" + col.getName() + "\")"]]
         }else {
             fields += [[name : javaName(col.getName(), false),
                         type : typeStr,
                         annos: "@Column(name =\"" + col.getName() + "\")"]]
         }
     }
 }

 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]
 }

Generate POJOs For Lombok.groovy 使用lombok插件之后可以采用如下脚本生成Lombok形式的pojo

import com.intellij.database.model.DasTable
import com.intellij.database.model.ObjectKind
import com.intellij.database.util.Case
import com.intellij.database.util.DasUtil

/*
 * Available context bindings:
 *   SELECTION   Iterable<DasObject>
 *   PROJECT     project
 *   FILES       files helper
 */

packageName = "com.ryb.pojo;"

typeMapping = [
  (~/(?i)int/)                      : "long",
  (~/(?i)float|double|decimal|real/): "double",
  (~/(?i)datetime|timestamp/)       : "java.sql.Timestamp",
  (~/(?i)date/)                     : "java.sql.Date",
  (~/(?i)time/)                     : "java.sql.Time",
  (~/(?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 = javaName(table.getName(), true)
  def fields = calcFields(table)
  def path = dir.getPath()
  def packageName = path.substring(path.lastIndexOf("java") + 5, path.length()).replaceAll("\\\\", ".")
  new File(dir, className + ".java").withPrintWriter { out -> generate(out, className, fields, packageName) }
}

def generate(out, className, fields, packageName) {
  out.println "package $packageName;"
  out.println ""
  out.println "import lombok.Data;"
  out.println ""
  out.println "@Data"
  out.println "public class $className {"
  out.println ""
  fields.each() {
    if (it.annos != "") out.println "\t${it.annos}"
    out.println "\tprivate ${it.type} ${it.name};"
  }
  out.println "}"
}

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
    fields += [[
                 name : javaName(col.getName(), false),
                 type : typeStr,
                 annos: ""]]
  }
}

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]
}