使用Spring Roo ，感受ROR式的开发

Roo是一种 Spring 开发的辅助工具，使用命令行操作来生成自动化项目，操作非常类似于rails

我这里使用spring tool suit来开发一个demo项目

首先新建个spring template project，然后选择template类型为Roo Wep App (based on Roo 1.0.0.RC1)
这样，便会通过roo的命令自动生成一个标准的maven web项目，里面含有最基本的Spring 配置

建好项目后，我们可以在project上运行roo shell
通过hint命令，我们可以很快的了解各种操作提示

首先，设置数据库

install jpa -provider HIBERNATE -database MYSQL

roo会帮你在配置文件applicationContext.xml中配置好了相应的数据源配置，并且在 pom.xml中已经添加jpa和数据库驱动等相关的依赖。

然后新建一个domain

new persistent class jpa -name ~.domain.Employee -testAutomatically

这时roo会帮我们生成Employee类，这时Employee类还没有任何字段，我们可以通过roo shell往里面加入一些字段

add field string -fieldName name -notNull -sizeMax 200
add field date jpa -fieldName birth -type java.util.Date
......

最终生成的Employee如下：

@Entity
@RooEntity
@RooJavaBean
@RooToString
public class Employee {

    @NotNull
    @Size(max = 200)
    private String name;

    @Temporal(TemporalType.TIMESTAMP)
    private Date birth;
}

你会发现，怎么没有get set呢？我们反编译看下编译后的class代码

// Decompiled by DJ v3.5.5.77 Copyright 2003 Atanas Neshkov  Date: 2009-8-8 21:37:43
// Home Page : http://members.fortunecity.com/neshkov/dj.html  - Check often for new version!
// Decompiler options: packimports(3) 
// Source File Name:   Employee.java

package com.javaeye.domain;

import java.util.Date;
import java.util.List;
import javax.persistence.EntityManager;
import org.aspectj.runtime.reflect.Factory;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.beans.factory.aspectj.*;

// Referenced classes of package com.javaeye.domain:
//            Employee_Roo_ToString, Employee_Roo_Entity, Employee_Roo_JavaBean

public class Employee
    implements ConfigurableObject
{

    public Employee()
    {
        org.aspectj.lang.JoinPoint joinpoint1 = Factory.makeJP(ajc$tjp_1, this, this);
        org.aspectj.lang.JoinPoint joinpoint = Factory.makeJP(ajc$tjp_0, this, this);
        if(this != null && getClass().isAnnotationPresent(org/springframework/beans/factory/annotation/Configurable) && AnnotationBeanConfigurerAspect.ajc$if_1((Configurable)getClass().getAnnotation(org/springframework/beans/factory/annotation/Configurable)))
            AnnotationBeanConfigurerAspect.aspectOf().ajc$before$org_springframework_beans_factory_aspectj_AbstractDependencyInjectionAspect$1$e854fa65(this);
        if(this != null && getClass().isAnnotationPresent(org/springframework/beans/factory/annotation/Configurable) && (this == null || !getClass().isAnnotationPresent(org/springframework/beans/factory/annotation/Configurable) || !AnnotationBeanConfigurerAspect.ajc$if_1((Configurable)getClass().getAnnotation(org/springframework/beans/factory/annotation/Configurable))) && AbstractDependencyInjectionAspect.ajc$if_0(joinpoint))
            AnnotationBeanConfigurerAspect.aspectOf().ajc$afterReturning$org_springframework_beans_factory_aspectj_AbstractDependencyInjectionAspect$2$1ea6722c(this);
        Employee_Roo_Entity.ajc$interFieldInit$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$entityManager(this);
        Employee_Roo_Entity.ajc$interFieldInit$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$id(this);
        Employee_Roo_Entity.ajc$interFieldInit$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$version(this);
        if(!AnnotationBeanConfigurerAspect.ajc$if_1((Configurable)getClass().getAnnotation(org/springframework/beans/factory/annotation/Configurable)) && AbstractDependencyInjectionAspect.ajc$if_0(joinpoint1))
            AnnotationBeanConfigurerAspect.aspectOf().ajc$afterReturning$org_springframework_beans_factory_aspectj_AbstractDependencyInjectionAspect$2$1ea6722c(this);
    }

    public static String ajc$privFieldGet$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$name(Employee employee)
    {
        return employee.name;
    }

    public static void ajc$privFieldSet$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$name(Employee employee, String s)
    {
        employee.name = s;
    }

    public static Date ajc$privFieldGet$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$birth(Employee employee)
    {
        return employee.birth;
    }

    public static void ajc$privFieldSet$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$birth(Employee employee, Date date)
    {
        employee.birth = date;
    }

    public static long countEmployees()
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$countEmployees();
    }

    public static EntityManager entityManager()
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$entityManager();
    }

    public static List findAllEmployees()
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$findAllEmployees();
    }

    public static Employee findEmployee(Long long1)
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$findEmployee(long1);
    }

    public static List findEmployeeEntries(int i, int j)
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$findEmployeeEntries(i, j);
    }

    public void flush()
    {
Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$flush(this);
    }

    public Date getBirth()
    {
        return Employee_Roo_JavaBean.ajc$interMethod$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$getBirth(this);
    }

    public Long getId()
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$getId(this);
    }

    public String getName()
    {
        return Employee_Roo_JavaBean.ajc$interMethod$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$getName(this);
    }

    public Integer getVersion()
    {
        return Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$getVersion(this);
    }

    public void merge()
    {   Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$merge(this);
    }

    public void persist()
    {     Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$persist(this);
    }

    public void remove()
    {
        Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$remove(this);
    }

    public void setBirth(Date date)
    {
        Employee_Roo_JavaBean.ajc$interMethod$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$setBirth(this, date);
    }

    public void setId(Long long1)
    {
        Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$setId(this, long1);
    }

    public void setName(String s)
    {
        Employee_Roo_JavaBean.ajc$interMethod$com_javaeye_domain_Employee_Roo_JavaBean$com_javaeye_domain_Employee$setName(this, s);
    }

    public void setVersion(Integer integer)
    {
        Employee_Roo_Entity.ajc$interMethod$com_javaeye_domain_Employee_Roo_Entity$com_javaeye_domain_Employee$setVersion(this, integer);
    }

    public String toString()
    {
        return Employee_Roo_ToString.ajc$interMethod$com_javaeye_domain_Employee_Roo_ToString$com_javaeye_domain_Employee$toString(this);
    }

    private String name;
    private Date birth;
    public transient EntityManager ajc$interField$com_javaeye_domain$entityManager;
    public Long ajc$interField$com_javaeye_domain_Employee_Roo_Entity$id;
    public Integer ajc$interField$com_javaeye_domain_Employee_Roo_Entity$version;
    private static final org.aspectj.lang.JoinPoint.StaticPart ajc$tjp_0; /* synthetic field */
    private static final org.aspectj.lang.JoinPoint.StaticPart ajc$tjp_1; /* synthetic field */

    static 
    {
        Factory factory = new Factory("Employee.java", Class.forName("com.javaeye.domain.Employee"));
        ajc$tjp_0 = factory.makeSJP("initialization", factory.makeConstructorSig("1", "org.springframework.beans.factory.aspectj.ConfigurableObject", "", "", ""), 17);
        ajc$tjp_1 = factory.makeSJP("initialization", factory.makeConstructorSig("1", "com.javaeye.domain.Employee", "", "", ""), 17);
    }
}

经过反编译生成的class发现，通过domain类上面的roo注释，自动在类编译时加入get set，甚至我们发现了findAllEmployees，persist，remove，哈，这不是我们梦寐以求的充血模型吗？

原来，roo在为我们创建domain的时候自动为同一个domain创建了4个aspect(.aj files)，并在编译期动态为domain切入代码.
4个aspect分别是：
domainName_Roo_Configurable.aj(配置)
domainName_Roo_Entity.aj(加入orm持久)
domainName_Roo_JavaBean.aj(为字段生成get set)
domainName_Roo_ToString.aj(重写toString)


可见，使用roo我们彻底摆脱了在daomain里对各个属性写get set，并且使domain摇身一变为充血。

下一步，就是建Controller了，同样是一条语句

new controller automatic -formBackingObject ~.domain.Employee -name ~.web.CommentController

你会发现，EmployeeController，spring mvc的配置以及curd的jsp页面全部生成了

EmployeeController代码如下：

@RooWebScaffold(automaticallyMaintainView = true, formBackingObject = Employee.class)
@RequestMapping("/employee/**")
@Controller
public class EmployeeController {
}

在这里出现了一行@RooWebScaffold注解，做过rails的人会想，这不是rails里面的scaffold吗？没错，通过@RooWebScaffold注解，EmployeeController自动获得了curd的所有功能。

同样是生成controllerName_Roo_Controller.aj在编译期织入代码

我们来看看生成的EmployeeController_Roo_Controller.aj:

package com.javaeye.web;

privileged aspect EmployeeController_Roo_Controller {
    
    @org.springframework.web.bind.annotation.RequestMapping(value = "/employee", method = org.springframework.web.bind.annotation.RequestMethod.POST)    
    public java.lang.String EmployeeController.create(@org.springframework.web.bind.annotation.ModelAttribute("employee") com.javaeye.domain.Employee employee, org.springframework.validation.BindingResult result) {    
        if (employee == null) throw new IllegalArgumentException("A employee is required");        
        for(javax.validation.ConstraintViolation<com.javaeye.domain.Employee> constraint : javax.validation.Validation.buildDefaultValidatorFactory().getValidator().validate(employee)) {        
            result.rejectValue(constraint.getPropertyPath(), null, constraint.getMessage());            
        }        
        if (result.hasErrors()) {        
            return "employee/create";            
        }        
        employee.persist();        
        return "redirect:/employee/" + employee.getId();        
    }    
    
    @org.springframework.web.bind.annotation.RequestMapping(value = "/employee/form", method = org.springframework.web.bind.annotation.RequestMethod.GET)    
    public java.lang.String EmployeeController.createForm(org.springframework.ui.ModelMap modelMap) {    
        modelMap.addAttribute("employee", new com.javaeye.domain.Employee());        
        return "employee/create";        
    }    
    
    @org.springframework.web.bind.annotation.RequestMapping(value = "/employee/{id}", method = org.springframework.web.bind.annotation.RequestMethod.GET)    
    public java.lang.String EmployeeController.show(@org.springframework.web.bind.annotation.PathVariable("id") java.lang.Long id, org.springframework.ui.ModelMap modelMap) {    
        if (id == null) throw new IllegalArgumentException("An Identifier is required");        
        modelMap.addAttribute("employee", com.javaeye.domain.Employee.findEmployee(id));        
        return "employee/show";        
    }    
    
    @org.springframework.web.bind.annotation.RequestMapping(value = "/employee", method = org.springframework.web.bind.annotation.RequestMethod.GET)    
    public java.lang.String EmployeeController.list(org.springframework.ui.ModelMap modelMap) {    
        modelMap.addAttribute("employees", com.javaeye.domain.Employee.findAllEmployees());        
        return "employee/list";        
    }    
    
    @org.springframework.web.bind.annotation.RequestMapping(method = org.springframework.web.bind.annotation.RequestMethod.PUT)    
    public java.lang.String EmployeeController.update(@org.springframework.web.bind.annotation.ModelAttribute("employee") com.javaeye.domain.Employee employee, org.springframework.validation.BindingResult result) {    
        if (employee == null) throw new IllegalArgumentException("A employee is required");        
        for(javax.validation.ConstraintViolation<com.javaeye.domain.Employee> constraint : javax.validation.Validation.buildDefaultValidatorFactory().getValidator().validate(employee)) {        
            result.rejectValue(constraint.getPropertyPath(), null, constraint.getMessage());            
        }        
        if (result.hasErrors()) {        
            return "employee/update";            
        }        
        employee.merge();        
        return "redirect:/employee/" + employee.getId();        
    }    
    
    @org.springframework.web.bind.annotation.RequestMapping(value = "/employee/{id}/form", method = org.springframework.web.bind.annotation.RequestMethod.GET)    
    public java.lang.String EmployeeController.updateForm(@org.springframework.web.bind.annotation.PathVariable("id") java.lang.Long id, org.springframework.ui.ModelMap modelMap) {    
        if (id == null) throw new IllegalArgumentException("An Identifier is required");        
        modelMap.addAttribute("employee", com.javaeye.domain.Employee.findEmployee(id));        
        return "employee/update";        
    }    
    
    @org.springframework.web.bind.annotation.RequestMapping(value = "/employee/{id}", method = org.springframework.web.bind.annotation.RequestMethod.DELETE)    
    public java.lang.String EmployeeController.delete(@org.springframework.web.bind.annotation.PathVariable("id") java.lang.Long id) {    
        if (id == null) throw new IllegalArgumentException("An Identifier is required");        
        com.javaeye.domain.Employee.findEmployee(id).remove();        
        return "redirect:/employee";        
    }    
    
    @org.springframework.web.bind.annotation.InitBinder    
    public void EmployeeController.initBinder(org.springframework.web.bind.WebDataBinder binder) {    
        binder.registerCustomEditor(java.util.Date.class, new org.springframework.beans.propertyeditors.CustomDateEditor(new java.text.SimpleDateFormat("yyyy-M-d"), false));        
    }    
    
}

这样，Controller里不用写一行代码，就自动拥有了curd，而且，最新的roo使用了spring3.0，还支持了rest

好了，就这么简单，一个domain，一个Controller，我们就可以发布到tomcat中运行了。
不到5分钟，我们就可以生成了一个可运行的项目，是不是很有ror式的感觉啊？赶快来试试吧！

SpringSource 在简化java开发方向上做的努力让人敬佩。
不过不知道在通过annotation简化java语言和直接采用groovy这类动态语言方面，SpringSource是如何选择这个方向的。
这也可能是java社区所面临的选择。

Roo对于了解Spring的新动向很有帮助。不过这东西理念上跟grail很重合，springsource居心叵测啊

太强了。。。领教了。。这种手法还是第一次看到

一切皆有可能

我昨天晚上试一下这个工具，如果能支持数据库就好了，要不然一条一条命令来加Field，还是挺麻烦的。希望它下一版本能加上这个功能。

关键是开发的时候修改东西要不要重启Web服务器！！

批评两句.雕虫小极而已.

也许这么做开始的时候能省点力气.可是等到一年以后你来维护这些代码的时候,是不是还能象现在这么高兴呢?想想这个问题吧,如果答案是否定的,那么就趁早放弃吧.

那请赐教一下，跟您自己手写的代码相比，哪里不好维护了？

这个东西现在还不成熟，只是1.0 release. 我不知道ror的开发过程是什么样的，请有这方面经验的讲一下。我是想用它先做一个雏形，把一些基础代码都生成，在此基础上进行修改，增加功能。可能我用得不好，好像不太适合我这种需求。