一个博客项目-3分类管理

本文主要是介绍一个博客项目-3分类管理，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

分类管理页面
分类列表分页
分类新增、修改、删除

分类管理页面
- types.html可以在blogs基础上进行修改
- types-input.html可以再blogs-input基础上进行修改
分类列表分页
首先要做dao层和service层

TypeRepository.java

package com.lmr.blog.dao;import com.lmr.blog.po.Type;
import org.springframework.data.jpa.repository.JpaRepository;public interface TypeRepository extends JpaRepository<Type, Long> {Type findByName(String name);
}

TypeService.java

package com.lmr.blog.service;import com.lmr.blog.po.Type;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;/*** Created by limi on 2017/10/16.*/
public interface TypeService {Type saveType(Type type);Type getType(Long id);Type getTypeByName(String name);Page<Type> listType(Pageable pageable);Type updateType(Long id,Type type);void deleteType(Long id);
}

pageable是Spring Data库中定义的一个接口，用于构造翻页查询，是所有相关分页信息的一个抽象，通过该接口，我们可以得到和分页相关所有信息(例如pageNumber、pageSize等)，这样，Jpa就能通过pageable参数来得到一个带分页信息的SQL语句。
pageable参考

TypeServiceImpl.java

package com.lmr.blog.service;import com.lmr.blog.NotFoundException;
import com.lmr.blog.dao.TypeRepository;
import com.lmr.blog.po.Type;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;/*** Created by limi on 2017/10/16.*/
@Service
public class TypeServiceImpl implements TypeService {@Autowired //先进行注入private TypeRepository typeRepository;@Transactional  //增删改查都放在一个事务中@Overridepublic Type saveType(Type type) {return typeRepository.save(type);}@Transactional@Overridepublic Type getType(Long id) {//  Spring boot新版本中findByid,旧版本是findOne(id)return typeRepository.findById(id).orElse(null);}@Overridepublic Type getTypeByName(String name) {return typeRepository.findByName(name);}@Transactional@Overridepublic Page<Type> listType(Pageable pageable) {return typeRepository.findAll(pageable);}@Transactional@Overridepublic Type updateType(Long id, Type type) {Type t = typeRepository.findById(id).orElse(null);if (t == null) {throw new NotFoundException("不存在该类型");}BeanUtils.copyProperties(type,t);return typeRepository.save(t);}@Transactional@Overridepublic void deleteType(Long id) {typeRepository.deleteById(id);}
}

TypeController.java

package com.lmr.blog.web.admin;import com.lmr.blog.po.Type;
import com.lmr.blog.service.TypeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.web.PageableDefault;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;/*** Created by limi on 2017/10/16.*/@Controller
@RequestMapping("/admin")
public class TypeController {@Autowiredprivate TypeService typeService;@GetMapping("/types")public String types(@PageableDefault(size = 3,sort = {"id"},direction = Sort.Direction.DESC)Pageable pageable, Model model) {model.addAttribute("page",typeService.listType(pageable));return "admin/types";}@GetMapping("/types/input")public String input(Model model) {model.addAttribute("type", new Type());return "admin/types-input";}@GetMapping("/types/{id}/input")public String editInput(@PathVariable Long id, Model model) {model.addAttribute("type", typeService.getType(id));return "admin/types-input";}@PostMapping("/types")public String post(@Validated Type type,BindingResult result, RedirectAttributes attributes) {Type type1 = typeService.getTypeByName(type.getName());//  使用了后端校验，"name"必须与后端一致if (type1 != null) {result.rejectValue("name","nameError","不能添加重复的分类");}if (result.hasErrors()) {return "admin/types-input";}Type t = typeService.saveType(type);if (t == null ) {attributes.addFlashAttribute("message", "新增失败");} else {attributes.addFlashAttribute("message", "新增成功");}return "redirect:/admin/types";}@PostMapping("/types/{id}")public String editPost(@Validated Type type, BindingResult result, @PathVariable Long id, RedirectAttributes attributes) {Type type1 = typeService.getTypeByName(type.getName());if (type1 != null) {result.rejectValue("name","nameError","不能添加重复的分类");}if (result.hasErrors()) {return "admin/types-input";}Type t = typeService.updateType(id,type);if (t == null ) {attributes.addFlashAttribute("message", "更新失败");} else {attributes.addFlashAttribute("message", "更新成功");}return "redirect:/admin/types";}@GetMapping("/types/{id}/delete")public String delete(@PathVariable Long id,RedirectAttributes attributes) {typeService.deleteType(id);attributes.addFlashAttribute("message", "删除成功");return "redirect:/admin/types";}}