Spring MVC 数据绑定流程

　　由WebDataBinder进行数据的类型转换，格式化，校验；

　　其属性ConversionService进行数据的类型转换，格式化，其属性validator进行数据的校验，绑定流程的错误会绑定到功能处理方法的形参BingResult对象中；

　　

　　可进行细粒度的数据绑定，例如：

 电话号码:<input type="text" name="phoneNumber.content"/><br/>

　　以上请求的URL映射的功能处理方法的形参是User类型的，其有一个PhoneNumber类型的名为phoneNumber属性，该属性有一个名为content的String类型的属性；

　　

　　数据校验，使用BindingResult/Errors，必须紧跟对应的形参，绑定的结果会写进这个对象，要进行数据校验必须要导入hibernate-validator-5.2.2.Final.jar，validation-api-1.1.0.CR1.jar，涉及到报之间的兼容问题，要小心，以上两个是可行的；

@Entity
@Table(name = "user")
@NamedQueries({
    @NamedQuery(name = "User.findByUsername", query = "SELECT o FROM User as o WHERE o.username = ?")
})
public class User {
    
    @Column(name = "id")
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    
    @NotNull
    @Column(name = "username")
    private String username;
    
    @NotNull
    @Column(name = "password")
    private String password;
    
    @Transient
    private PhoneNumber phoneNumber;
    
    @Transient
    private String address;
    
//    @NotNull(message = "{user.position.error}")
    @Column(name = "position")
    private String position;
    
    @NumberFormat(style=Style.NUMBER, pattern="#,###")
    private Integer asset;
    

    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;
    }

    public PhoneNumber getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(PhoneNumber phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getPosition() {
        return position;
    }

    public void setPosition(String position) {
        this.position = position;
    }
    
    public Integer getAsset() {
        return asset;
    }

    public void setAsset(Integer asset) {
        this.asset = asset;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result
                + ((position == null) ? 0 : position.hashCode());
        result = prime * result
                + ((username == null) ? 0 : username.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        User other = (User) obj;
        if (position == null) {
            if (other.position != null)
                return false;
        } else if (!position.equals(other.position))
            return false;
        if (username == null) {
            if (other.username != null)
                return false;
        } else if (!username.equals(other.username))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return username;
    }
    
}

　　其中 @NotNull 就是用于校验的注解，如果为null，Spring就会把错误绑定到BindingResult/Errors；

 

　　详细的源代码流程如下：