关于SpringBoot学习记录2.0

了解基础配置和Freemarker内容持久化类和映射文件关于栏截器的使用动态查询功能实现（初步学习内容，还需要进一步学习）总结和个人建议

了解基础配置和Freemarker内容

1.了解application.properties基本设置和hibernate数据库配置

#端口配置，默认8080 server.port=8888 #项目请求，默认/ server.servlet.context-path=/Test #自定义属性 HelloWorld=hello world!这是我第一个Spring Boot项目! #自定义属性(有前缀，和proerties包下配合方便使用) mysql.jdbcName=com.mysql.cj.jdbc.Driver mysql.dbUrl=jdbc:mysql://localhost:3306/test_itcast?serverTimezone=GMT mysql.userName=root mysql.passWord=123456 #数据库相关配置 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/test_itcast?serverTimezone=GMT spring.datasource.username=root spring.datasource.password=123456

2.了解Freemarker还有Controller 一、因为springboot不推荐jsp，所以本次学习不使用jsp相关知识。 二、这次学习Freemarker模板引擎，首先就是就是后缀.ftl，还有一些标签后面用到再说明。 三、@Controller和@RestController区别：用法上@Controller+@ResponseBody=@RestController，再者就是@RestController一般用于返回JSON。

持久化类和映射文件

1.了解application.properties基本设置（自动更新数据库）

spring.jpa.show-sql=true spring.jpa.hibernate.ddl-auto=update

2.Entity类(注解@Entity，@Table表，@Id主键，@GenertedValue自增)

@Entity @Table(name="t_user") public class User { @Id @GeneratedValue private Integer id; @Column(length = 45) private String username; @Column(length = 45) private String password; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }

3.Dao层

public interface UserDao extends JpaRepository<User,Integer> { //自定义查询 @Query("select b from User b where b.username like %?1%") public List<User> fineByUsername(String username); @Query(value = "select * from t_user order by RAND() limit ?1",nativeQuery = true) public List<User> randomList(Integer n); }

Controller层

@Controller @RequestMapping("/user") public class UserController { @Resource private UserDao userDao; @RequestMapping("/toadd") public String toadd(){ return "add"; } //显示列表 @RequestMapping("/userlist") private ModelAndView userlist(){ ModelAndView mav=new ModelAndView(); mav.addObject("userlist",userDao.findAll()); mav.setViewName("userlist"); return mav; } //添加 @RequestMapping(value = "/add",method = RequestMethod.POST) private String add(User user){ userDao.save(user); return "redirect:/user/userlist"; } //根据id查询 @RequestMapping("/preupdate/{id}") public ModelAndView preupdate(@PathVariable("id") Integer id){ ModelAndView mav=new ModelAndView(); mav.addObject("user",userDao.getOne(id)); mav.setViewName("update"); return mav; } //修改 @RequestMapping(value = "/update",method = RequestMethod.POST) private String update(User user){ userDao.save(user); return "redirect:/user/userlist"; } //删除 @RequestMapping(value = "/delete",method = RequestMethod.GET) private String delete(Integer id){ userDao.deleteById(id); return "redirect:/user/userlist"; }

关于栏截器的使用

1.了解SpringBoot拦截器配置 configuration用来配置拦截器栏截的请求和静态资源。 interceptor配置栏截器内容 2.基本代码格式 configuration包下(基本设置，主要介绍配置addInterceptors方法)：

@Configuration public class SessionConfiguration implements WebMvcConfigurer { //注入拦截器LoginInterceptor @Autowired private LoginInterceptor loginInterceptor; //配置静态资源的，html，js，css。。。等 @Override public void addResourceHandlers(ResourceHandlerRegistry registry){ } //注册拦截器 @Override public void addInterceptors(InterceptorRegistry registry){ //addPathPatterns("/**") 表示拦截所有请求， //excludePathPatterns("/login") 表示除了/login请求之外 registry.addInterceptor(loginInterceptor).addPathPatterns("/**").excludePathPatterns("/login"); } }

interceptor包下(这里主要用到PreHandle，即请求前栏截处理)：

//添加Component注解，否则SessionConfiguration中无法注入 @Component public class LoginInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { HttpSession session=request.getSession(); String user=(String) session.getAttribute("USER_SESSION"); if(user==null){ request.getRequestDispatcher("/login").forward(request, response); return false; }else { return true; } } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { } }

动态查询功能实现（初步学习内容，还需要进一步学习）

//动态查询 @RequestMapping("/list") public ModelAndView list(User user){ ModelAndView mav=new ModelAndView(); List<User> userList=userDao.findAll(new Specification<User>(){ @Override public Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) { Predicate predicate=criteriaBuilder.conjunction(); if(user!=null){ if(user.getUsername()!=null && !"".equals(user.getUsername())){ predicate.getExpressions().add(criteriaBuilder.like(root.get("username"),"%"+user.getUsername()+"%")); } if(user.getPassword()!=null && !"".equals(user.getPassword())){ predicate.getExpressions().add(criteriaBuilder.like(root.get("password"),"%"+user.getPassword()+"%")); } } return predicate; } }); mav.addObject("userlist",userList); mav.setViewName("userlist"); return mav; }

总结和个人建议

本次学习内容比较杂，不是非常系统和深入，最好是多多学习数据库的有关方面的使用。还有一些与前端插件配合使用的方法。