UpdateWrapper修改指定的列

UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
updateWrapper.eq("id","1").set("name", "tom");
Integer rows = userMapper.update(null, updateWrapper);

LambdaUpdateWrapper

LambdaUpdateWrapper<OilUser> updateWrapper= new LambdaUpdateWrapper<>();
updateWrapper.set(OilUser::getUsername, user.getUsername());
updateWrapper.set(OilUser::getTel, user.getTel());
updateWrapper.set(OilUser::getEmail, user.getEmail());
updateWrapper.eq(OilUser::getId, user.getId());
userMapper.update(null, updateWrapper);

LambdaUpdateWrapper<User> lambdaUpdateWrapper = new LambdaUpdateWrapper<>();
lambdaUpdateWrapper.eq(User::getId, user.getId()).set(User::getAge, 34);
Integer rows = userMapper.update(null, lambdaUpdateWrapper);

注意：

xxxMapper.update(null, updateWrapper);

第一个参数需要设置null，这样就只会更新set的字段
LambdaUpdateChainWrapper

LambdaUpdateChainWrapper<User> lambdaUpdateChainWrapper = new LambdaUpdateChainWrapper<>(userMapper);

boolean update = lambdaUpdateChainWrapper.eq(User::getRealName, "tom").set(User::getAge, 33).update();
        
//分步写
/*
lambdaUpdateChainWrapper.eq(User::getRealName, "tom");
if (user.getAge == 33) {
    lambdaUpdateChainWrapper.set(User::getAge, 33);
}
lambdaUpdateChainWrapper.update();
*/