Springmvc获取前台请求数据过程解析

// RequestMapping:指定方法对应的请求地址
  //return:页面地址，表示方法执行完成之后跳转到对应的页面(转发)
  //springmvc：接收请求参数，直接在方法的参数中定义名称与传递参数名一致的形参即可
  //name：会自动接收请求传递的name值
  @RequestMapping("/hello")
  public String hello(String name,Integer age){
    System.out.println("name:"+name+",age:"+age);
    return "index.jsp";
  }

public class User {

  private Integer id;
private String name;
private Integer age;
private String sex;
private String addr;
}

    @RequestMapping("/saveUser")
    public String saveUser(User user){
       System.out.println("User:"+user);
       return "index.jsp";
    }

  //通过对象来接收前台的多个同名数据，两种方式，一种是数组，一种是List集合；
  //private String[] hobbies;
   private List<String> hobbies;
  public String[] getHobbies() {
    return hobbies;
  }

  public void setHobbies(String[] hobbies) {
    this.hobbies = hobbies;
  }

  public List<String> getHobbies() {
    return hobbies;
  }

  public void setHobbies(List<String> hobbies) {
    this.hobbies = hobbies;
  }

@RequestMapping("/saveUser")
  public String saveAdmin(User user, String[] hobbies){
    System.out.println("user:"+user);
    System.out.println(Arrays.toString(hobbies));
    return "index.jsp";
  }

public class Role {
  private String name;
  private Integer id;
  @Override
  public String toString() {
    return "Role{" +
        "name='" + name + '\'' +
        "id='" + id + '\'' +
        '}';
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public Integer getId() {
    return id;
  }
  public void setId(Integer id) {
    this.id = id;
  }
}

 //用来接收前台的数据
  private Role role;
  public Role getRole() {
    return role;
  }

  public void setRole(Role role) {
    this.role = role;
  }

public String saveUser(User user, String[] hobbies){
    System.out.println("User:"+user);
    System.out.println(Arrays.toString(hobbies));
    System.out.println("role:"+user.getRole()); 
    return "index.jsp"; 
}

  //通过map接收前台的值
  private Map<String,String> conditions;
  public Map<String, String> getConditions() {
    return conditions;
  }
  public void setConditions(Map<String, String> conditions) {
    this.conditions = conditions;
  }

//map :将所有请求数据封装到map中
  // @RequestParam("name")：指定向请求中获取数据 ==>request.getParameter
  //required = false:是否必传  defaultValue:默认值
  @RequestMapping("/saveUser")
  public String saveUser(User user, String[] hobbies,
              @RequestParam(name="name",required = false,defaultValue = "username") String username,
              @RequestParam HashMap map){
    System.out.println("User:"+user);
    System.out.println("role:"+user.getRole());
    System.out.println(Arrays.toString(hobbies));
    System.out.println("map:"+map);
    System.out.println("username:"+username);    System.out.println("conditions:"+user.getConditions());    return "index.jsp"; }