修改(update)

Mapper 内置方法

• update(T)：实体类修改
• update(Model)：Model类修改
• saveOrUpdate(T)：实体类保存或修改
• update(T,forceUpdateFields)：实体类修改，可强制某些字段修改（null值会被替换层数据库里的NULL）
• update(Model,forceUpdateFields)：Model修改，可强制某些字段修改（null值会被替换层数据库里的NULL）
• update(T,Where)：根据where，实体类批量修改
• update(Model,Where)：根据where，Model类批量修改
• update(List<T>)：多个实体类修改
• update(List<T>,forceUpdateFields)：多个实体类修改，可强制某些字段修改（null值会被替换层数据库里的NULL）

基于实体类

public class Demo {
    @Autowired
    private SysUserMapper sysUserMapper;
    
    public void update() {
        SysUser sysUser = new SysUser();
        sysUser.setId(1);
        sysUser.setUserName("demo");
        sysUserMapper.update(sysUser);
    }
}

基于Model类

Model类为了update时，不用处理太多的字段，只修改部分字段；同时也简单类的转换，方便快捷

Model类

@Data
public class SysUserModel implements Model<SysUser> {

    private Integer id;

    private String userName;
   
    
    //private String password;

    //private Integer roleId;

    private LocalDateTime createTime;
}

基于Model类 update

public class Demo {
    @Autowired
    private SysUserMapper sysUserMapper;
    
    public void update() {
        SysUserModel sysUser = new SysUserModel();
        sysUser.setId(1);
        sysUser.setUserName("demo");
        sysUserMapper.update(sysUser);
    }
}

动态update

基于UpdateChain(强大)

可构建复杂的场景

public class Demo {
    @Autowired
    private SysUserMapper sysUserMapper;

    public void update() {
        UpdateChain.of(sysUserMapper)
                .update(SysUser.class)
                .set(SysUser::getUserName, "new userName")
                .eq(SysUser::getId, 1)
                .execute();
    }
}

基于where,（批量）修改

public class Demo {
    @Autowired
    private SysUserMapper sysUserMapper;

    public void update() {
        SysUser sysUser=new SysUser();
        sysUser.setUserName("where UPDATE");
        sysUserMapper.update(sysUser,where -> {
            where.gt(SysUser::getId,100);
        });
    }
}

update 列自增,例如version=version +1

也可以 其他自身操作

public class Demo {
    @Autowired
    private SysUserMapper sysUserMapper;
    
    public void update() {
        UpdateChain.of(sysUserMapper)
            .set(SysUser::getVersion, c -> c.plus(1))
            .eq(SysUser::getId, 1)
            .execute();
    }
}